Conferece call management screen UI adjustment.

Including:
- change action icon color
- hide TextView for name if name is empty
- if name is empty, use number to generate avatar
- don't show number type
Bug: 67053842
Test: manual
PiperOrigin-RevId: 175188810
Change-Id: I4ba40e5332d7b8567932360d36c8dc6ec3d604a5