Fix GULUserDefaults dependency

Author: Chuan Ren

Auth/FirebaseAuthUI/FUIAuth.m

@@ -22,7 +22,6 @@
 #import <FirebaseCore/FIROptions.h>
 #import <FirebaseAuth/FIRAuth.h>
 #import <FirebaseAuth/FirebaseAuth.h>
-#import <GoogleUtilities/GULUserDefaults.h>
 #import "FUIAuthBaseViewController_Internal.h"
 #import "FUIAuthErrors.h"
 #import "FUIAuthErrorUtils.h"

samples/objc/Podfile

@@ -5,6 +5,4 @@ target 'FirebaseUI-demo-objc' do
 
   pod 'FirebaseUI', :path => '../../'
   pod 'Firebase/DynamicLinks'
-
-  pod 'GoogleUtilities/UserDefaults'
 end