Added waits to StatusBarHelperImpl for changeToDayModeTest and changeToNightModeTest

Test: https://android-build.corp.google.com/builds/abtd/run/L77800030008247775
Bug: 356986808
Change-Id: I88a262c8f4e5189f622bcc3afe71a9f30f33748d
1 file changed