fix(auth, ios): fix scoping of import for message.g.h, could cause incompatibility with other packages (#11300)

Author: Lyokone

packages/firebase_auth/firebase_auth/ios/Classes/Private/FLTPhoneNumberVerificationStreamHandler.h

@@ -11,7 +11,7 @@
 #endif
 
 #import <Firebase/Firebase.h>
-#import "messages.g.h"
+#import <firebase_auth/messages.g.h>
 
 #import <Foundation/Foundation.h>
 

packages/firebase_auth/firebase_auth/ios/Classes/Private/PigeonParser.h

@@ -6,7 +6,7 @@
 
 #import <Firebase/Firebase.h>
 #import <Foundation/Foundation.h>
-#import "messages.g.h"
+#import <firebase_auth/messages.g.h>
 
 @interface PigeonParser : NSObject
 

packages/firebase_auth/firebase_auth/ios/Classes/Public/FLTFirebaseAuthPlugin.h

@@ -14,7 +14,7 @@
 #import <AuthenticationServices/AuthenticationServices.h>
 #import <Foundation/Foundation.h>
 #import <firebase_core/FLTFirebasePlugin.h>
-#import "messages.g.h"
+#import <firebase_auth/messages.g.h>
 
 @interface FLTFirebaseAuthPlugin
     : FLTFirebasePlugin <FlutterPlugin,