Delay setting night mode to show ripple animation am: e7b91d59f8 am: 8bb4fdc333

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/ThemePicker/+/15093525

Change-Id: I513f99d46af18dfc11f3ae9d97700ba71f9a0a5f