Implement some UI changes.

Including:
- merge end call button with other buttons
- add ripple effect for buttons
- adjust elevation according to material design guide
- add triangle in expanded view
Bug: 67605985
Test: manual
PiperOrigin-RevId: 174253861
Change-Id: I7b5315245a322235efb39a9cda26b8686cc7bbf9
12 files changed