Remove the qsb layout margin and update the margin horizontal of it's...

Remove the qsb layout margin and update the margin horizontal of it's container am: 8b466ddc am: e2fc1d85

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/ThemePicker/+/11592769

Change-Id: I1487cd1a368f6f1061efbf194374062a8d236d65