Fix locale for UI tests

Author: fr0l

Signal.xcodeproj/xcshareddata/xcschemes/Signal.xcscheme

@@ -38,6 +38,16 @@
             ReferencedContainer = "container:Signal.xcodeproj">
          </BuildableReference>
       </MacroExpansion>
+      <CommandLineArguments>
+         <CommandLineArgument
+            argument = "-AppleLocale en_US"
+            isEnabled = "YES">
+         </CommandLineArgument>
+         <CommandLineArgument
+            argument = "-AppleLanguages (en)"
+            isEnabled = "YES">
+         </CommandLineArgument>
+      </CommandLineArguments>
       <EnvironmentVariables>
          <EnvironmentVariable
             key = "runningTests_dontStartApp"