fix(tablet): fix magnification banner in dark mode am: 44660662 am: 05723287

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Settings/+/21466797



Change-Id: I949c5a2c919ee266ae7f28bd9c6ab4f3d55013fe
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>