[Output Switcher] Update device selection layout

Update device selection layout to match with UX markup.
1. divide device item part with group part, to allow both transfer and
   grouping.
2. update checkbox image to match with markup.

guard this change by flag.

Bug: 249371764
Bug: 255126338
Test: atest MediaOutputAdapterTest MediaOutputControllerTest MediaOutputBaseDialogTest MediaOutputDialogTest
Change-Id: I6e92a40f25ea940286cb5ca49aa0193fd9f406a5