Fix RCTDevLoadingView dismiss button not appearing (#54696)

Summary:
Pull Request resolved: #54696

Changelog: [iOS][Fixed] - Fixed dismiss button not appearing consistently in dev loading view

D87465522 introduced lazy initialization to reuse views across multiple `showMessage` calls for better performance. However, this exposed two bugs:

1. **Missing button bug**: Button creation was inside the `if (self->_container == nullptr)` block, which now only executes once. If the first call had `dismissButton=NO`, subsequent calls with `dismissButton=YES` would skip button creation since the container already existed.

2. **Button text wrapping bug**: The button didn't have compression resistance priority set, so Auto Layout could compress it to fit the layout, causing the text to wrap.

This fixes both issues by:
- Moving button creation/removal logic outside the container initialization so it runs on every call and dynamically adds or removes the button based on the current `dismissButton` parameter
- Setting compression resistance and content hugging priorities on the button to prevent it from being compressed, forcing the message label to wrap instead
- Resetting all UI elements in `hide()` to ensure clean state between loading sessions

The performance optimization from D87465522 is preserved - views are still reused during rapid Metro progress updates.

Reviewed By: javache

Differential Revision: D87870932

fbshipit-source-id: 052d4a0685ee288e3b4bf974b203e4f29c652436

Author: emily8rown

packages/react-native/React/CoreModules/RCTDevLoadingView.mm

@@ -121,49 +121,61 @@ - (void)showMessage:(NSString *)message
       self->_label.translatesAutoresizingMaskIntoConstraints = NO;
       self->_label.font = [UIFont monospacedDigitSystemFontOfSize:12.0 weight:UIFontWeightRegular];
       self->_label.textAlignment = NSTextAlignmentCenter;
+      [self->_container addSubview:self->_label];
+      self->_label.numberOfLines = 0;
     }
     self->_label.textColor = color;
     self->_label.text = message;
-    self->_label.numberOfLines = 0;
 
     if (self->_container == nullptr) {
       self->_container = [[UIView alloc] init];
       self->_container.translatesAutoresizingMaskIntoConstraints = NO;
       UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(hide)];
       [self->_container addGestureRecognizer:tapGesture];
       self->_container.userInteractionEnabled = YES;
-
-      if (dismissButton) {
-        CGFloat hue = 0.0;
-        CGFloat saturation = 0.0;
-        CGFloat brightness = 0.0;
-        CGFloat alpha = 0.0;
-        [backgroundColor getHue:&hue saturation:&saturation brightness:&brightness alpha:&alpha];
-        UIColor *darkerBackground = [UIColor colorWithHue:hue
-                                               saturation:saturation
-                                               brightness:brightness * 0.7
-                                                    alpha:1.0];
-
-        UIButtonConfiguration *buttonConfig = [UIButtonConfiguration plainButtonConfiguration];
-        buttonConfig.attributedTitle = [[NSAttributedString alloc]
-            initWithString:@"Dismiss ✕"
-                attributes:@{NSFontAttributeName : [UIFont systemFontOfSize:11.0 weight:UIFontWeightRegular]}];
-        buttonConfig.contentInsets = NSDirectionalEdgeInsetsMake(6, 12, 6, 12);
-        buttonConfig.background.backgroundColor = darkerBackground;
-        buttonConfig.background.cornerRadius = 10;
-        buttonConfig.baseForegroundColor = color;
-
-        UIAction *dismissAction = [UIAction actionWithHandler:^(__kindof UIAction *_Nonnull action) {
-          [self hide];
-        }];
-        self->_dismissButton = [UIButton buttonWithConfiguration:buttonConfig primaryAction:dismissAction];
-        self->_dismissButton.translatesAutoresizingMaskIntoConstraints = NO;
-        [self->_container addSubview:self->_dismissButton];
-      }
       [self->_container addSubview:self->_label];
     }
     self->_container.backgroundColor = backgroundColor;
 
+    // Handle button creation/removal dynamically based on dismissButton parameter
+    if (dismissButton && self->_dismissButton == nullptr) {
+      CGFloat hue = 0.0;
+      CGFloat saturation = 0.0;
+      CGFloat brightness = 0.0;
+      CGFloat alpha = 0.0;
+      [backgroundColor getHue:&hue saturation:&saturation brightness:&brightness alpha:&alpha];
+      UIColor *darkerBackground = [UIColor colorWithHue:hue
+                                             saturation:saturation
+                                             brightness:brightness * 0.7
+                                                  alpha:1.0];
+
+      UIButtonConfiguration *buttonConfig = [UIButtonConfiguration plainButtonConfiguration];
+      buttonConfig.attributedTitle = [[NSAttributedString alloc]
+          initWithString:@"Dismiss ✕"
+              attributes:@{NSFontAttributeName : [UIFont systemFontOfSize:11.0 weight:UIFontWeightRegular]}];
+      buttonConfig.contentInsets = NSDirectionalEdgeInsetsMake(6, 12, 6, 12);
+      buttonConfig.background.backgroundColor = darkerBackground;
+      buttonConfig.background.cornerRadius = 10;
+      buttonConfig.baseForegroundColor = color;
+
+      UIAction *dismissAction = [UIAction actionWithHandler:^(__kindof UIAction *_Nonnull action) {
+        [self hide];
+      }];
+      self->_dismissButton = [UIButton buttonWithConfiguration:buttonConfig primaryAction:dismissAction];
+      self->_dismissButton.translatesAutoresizingMaskIntoConstraints = NO;
+
+      // Prevent button from being compressed - force label to wrap instead
+      [self->_dismissButton setContentCompressionResistancePriority:UILayoutPriorityRequired
+                                                            forAxis:UILayoutConstraintAxisHorizontal];
+      [self->_dismissButton setContentHuggingPriority:UILayoutPriorityRequired
+                                              forAxis:UILayoutConstraintAxisHorizontal];
+
+      [self->_container addSubview:self->_dismissButton];
+    } else if (!dismissButton && self->_dismissButton != nullptr) {
+      [self->_dismissButton removeFromSuperview];
+      self->_dismissButton = nullptr;
+    }
+
     UIWindow *mainWindow = RCTKeyWindow();
     if (self->_window == nullptr) {
       UIWindowScene *windowScene = mainWindow.windowScene;
@@ -245,6 +257,9 @@ - (void)showMessage:(NSString *)message
           self->_window.frame = windowFrame;
           self->_window.hidden = YES;
           self->_window = nil;
+          self->_container = nil;
+          self->_label = nil;
+          self->_dismissButton = nil;
           self->_hiding = false;
         }];
   });