Ignore fragment attr from ext authenticator resource

Bug: 341886134
Test: Unit Test
Test: Manual - see ticket for steps
Flag: EXEMPT <security>
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:2cb9b10ed97b1b9b29661115789605a762f3c2ef)
Merged-In: Id91c2b3b6d16ba3702ee2cd6723365a4db52863b
Change-Id: Id91c2b3b6d16ba3702ee2cd6723365a4db52863b