Protect GrantCredentialsPermissionActivity against overlay. am: f45dcfe1f5 am: 3f47c701f1 am: 765788de9a am: 3be814cbff am: 85e5d308e8 am: 42cc210e32

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/13029378

Change-Id: Ia9ca5113346ebbb5400658dd42de7e756a3cddb6