[Output Switcher] UI polish and A11y bug fix

1. update radius to match rounded corners
2. update seekbar update to cover cases icon corner erea not update
3. ignore update action on icon and replace with icon area, which is
   bigger

Bug: 282119404
Bug: 282125409
Bug: 282192631
Bug: 282192967
Test: atest MediaOutputAdapterTest MediaOutputControllerTest MediaOutputBaseDialogTest MediaOutputDialogTest
Change-Id: I8b5e6463acaf406cdfc29e11fd40cb306af7a3ef