[0.76] Update ReactNativeFlipper deprecation to ERROR (#46840)

Author: cortinico

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/flipper/ReactNativeFlipper.kt

@@ -19,15 +19,15 @@ import com.facebook.react.ReactInstanceManager
     message =
         "ReactNative/Flipper integration is deprecated. Please remove the call to initializeFlipper from your MainApplication.java",
     replaceWith = ReplaceWith(""),
-    level = DeprecationLevel.WARNING)
+    level = DeprecationLevel.ERROR)
 public object ReactNativeFlipper {
   @Suppress("UNUSED_PARAMETER")
   @JvmStatic
   @Deprecated(
       message =
           "ReactNative/Flipper integration is deprecated. Please remove the call to initializeFlipper from your MainApplication.java",
       replaceWith = ReplaceWith(""),
-      level = DeprecationLevel.WARNING)
+      level = DeprecationLevel.ERROR)
   public fun initializeFlipper(context: Context, reactInstanceManager: ReactInstanceManager) {
     // no-op
   }