fix(ExceptionNotifyServiceProvider): Remove unused notFound baseline

- Delete the unnecessary class.notFound.neon file
- Update loader.neon to reflect the removal and correct total errors
- Simplify code in ExceptionNotifyServiceProvider by removing an unnecessary class existence check

Author: guanguans

baselines/class.notFound.neon

@@ -1,4 +1,3 @@
-# total 3 errors
+# total 2 errors
 includes:
-    - class.notFound.neon
     - disallowed.function.neon

baselines/loader.neon

@@ -115,10 +115,6 @@ private function registerCommands(): self
 
     private function addSectionToAboutCommand(): void
     {
-        if (!class_exists(InstalledVersions::class)) {
-            return;
-        }
-
         AboutCommand::add('Laravel Exception Notify', static function (): array {
             $package = 'guanguans/laravel-exception-notify';