fix: resolve FlutterSceneLifeCycleDelegate conformance guard (#18385)

Author: SelaseKay

packages/firebase_auth/firebase_auth/ios/firebase_auth/Sources/firebase_auth/include/Public/FLTFirebaseAuthPlugin.h

@@ -34,8 +34,7 @@
                          ASAuthorizationControllerDelegate,
                          ASAuthorizationControllerPresentationContextProviding
 #if !TARGET_OS_OSX
-#if __has_include(<Flutter/FlutterSceneLifeCycleDelegate.h>) || \
-    defined(FlutterSceneLifeCycleDelegate)
+#if __has_include(<Flutter/FlutterSceneLifeCycle.h>)
                          ,
                          FlutterSceneLifeCycleDelegate
 #endif

packages/firebase_messaging/firebase_messaging/ios/firebase_messaging/Sources/firebase_messaging/include/FLTFirebaseMessagingPlugin.h

@@ -54,7 +54,7 @@ API_AVAILABLE(ios(10.0))
                                                            FLTFirebasePlugin,
                                                            FIRMessagingDelegate,
                                                            UIApplicationDelegate
-#if __has_include(<Flutter/FlutterSceneLifeCycleDelegate.h>) || defined(FlutterSceneLifeCycleDelegate)
+#if __has_include(<Flutter/FlutterSceneLifeCycle.h>)
                                                            ,
                                                            FlutterSceneLifeCycleDelegate
 #endif
@@ -63,7 +63,7 @@ API_AVAILABLE(ios(10.0))
 @interface FLTFirebaseMessagingPlugin : FLTFirebasePlugin <FlutterPlugin,
                                                            FLTFirebasePlugin,
                                                            FIRMessagingDelegate
-#if __has_include(<Flutter/FlutterSceneLifeCycleDelegate.h>) || defined(FlutterSceneLifeCycleDelegate)
+#if __has_include(<Flutter/FlutterSceneLifeCycle.h>)
                                                            ,
                                                            FlutterSceneLifeCycleDelegate
 #endif