Integrating ColorContrast in Picker

This CL aims at adding changes for integrating ColorContrast
functionality in WallpaperPicker App.

Bug: b/326108993
Test: Tested by building and installing picker on local and checking if
option appears or not, and testing dark/light theme
Flag: N/A

Change-Id: I8a9ec55d4aef621d2ea74be5373fc5137aa49b3b
19 files changed