Add small clock option description am: c8406412

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/ThemePicker/+/24354978



Change-Id: I213c9ba5a60a1b7d915cbd4563e1887801914830
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>