Clean up enable_output_switcher_redesign flag.

Bug: 444172986
Test: atest android.media.router.cts.OutputSwitcherTest
Flag: EXEMPT TEST_ONLY
Cherrypick-From: https://googleplex-android-review.googlesource.com/q/commit:0eeec88445751aeda4ed63b349ba5e67016833cf
Merged-In: Ibdf68c66583f34abed630cbf5ab4135832ac9631
Change-Id: Ibdf68c66583f34abed630cbf5ab4135832ac9631
1 file changed