[Cleanup]: Migrate away from GULSecureCoding in Firebase 11

[ncooke3]

Description

FirebaseMessaging uses GULSecureCoding which provides a compat API (https://github.com/google/GoogleUtilities/blob/main/GoogleUtilities/Environment/Public/GoogleUtilities/GULSecureCoding.h) that will no longer be needed when the minimum version is raised in Firebase 11.

FirebaseMessaging/Sources/FIRMessagingPubSub.m:#import <GoogleUtilities/GULSecureCoding.h>
FirebaseMessaging/Sources/FIRMessagingPubSub.m-#import <GoogleUtilities/GULUserDefaults.h>
FirebaseMessaging/Sources/FIRMessagingPubSub.m-#import "FirebaseMessaging/Sources/FIRMessagingDefines.h"
FirebaseMessaging/Sources/FIRMessagingPubSub.m-#import "FirebaseMessaging/Sources/FIRMessagingLogger.h"
FirebaseMessaging/Sources/FIRMessagingPubSub.m-#import "FirebaseMessaging/Sources/FIRMessagingPendingTopicsList.h"
FirebaseMessaging/Sources/FIRMessagingPubSub.m-#import "FirebaseMessaging/Sources/FIRMessagingTopicOperation.h"
--
FirebaseMessaging/Sources/FIRMessagingPubSub.m:  NSData *pendingData = [GULSecureCoding archivedDataWithRootObject:topicsList error:&error];
FirebaseMessaging/Sources/FIRMessagingPubSub.m-  if (error) {
FirebaseMessaging/Sources/FIRMessagingPubSub.m-    FIRMessagingLoggerError(kFIRMessagingMessageCodePubSubArchiveError,
FirebaseMessaging/Sources/FIRMessagingPubSub.m-                            @"Failed to archive topic list data %@", error);
FirebaseMessaging/Sources/FIRMessagingPubSub.m-    return;
FirebaseMessaging/Sources/FIRMessagingPubSub.m-  }
--
FirebaseMessaging/Sources/FIRMessagingPubSub.m:    subscriptions = [GULSecureCoding
FirebaseMessaging/Sources/FIRMessagingPubSub.m-        unarchivedObjectOfClasses:[NSSet setWithObjects:FIRMessagingPendingTopicsList.class, nil]
FirebaseMessaging/Sources/FIRMessagingPubSub.m-                         fromData:pendingData
FirebaseMessaging/Sources/FIRMessagingPubSub.m-                            error:&error];
FirebaseMessaging/Sources/FIRMessagingPubSub.m-    if (error) {
FirebaseMessaging/Sources/FIRMessagingPubSub.m-      FIRMessagingLoggerError(kFIRMessagingMessageCodePubSubUnarchiveError,

API Proposal

No response

Firebase Product(s)

Messaging