fix(ios, messaging): serialize google.c.sender.id to message.from

This from key was provided in react-native-firebase v5 and somewhere
along the way it was lost, the iOS SDK now passes this key through the
internal google.c.sender.id key in userInfo, use it as well.

packages/messaging/ios/RNFBMessaging/RNFBMessagingSerializer.m

@@ -63,7 +63,7 @@ + (NSDictionary *)remoteMessageUserInfoToDict:(NSDictionary *)userInfo {
     }
 
     // message.from
-    if ([key isEqualToString:@"from"]) {
+    if ([key isEqualToString:@"from"] || [key isEqualToString:@"google.c.sender.id"]) {
       message[@"from"] = userInfo[key];
       continue;
     }