Merge "Revert "Revert "Making mirror slider appear when brightness slider is used in split shade""" into sc-v2-dev am: ed4d4329ea

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15432522

Change-Id: I9acaa75f44f3ce48446b7bc135ad0c3062a625c7