These changes are in response to an API review on the recent addition of the CallControl#setMuteState API.

API changes:
- change setMuteState to requestMuteState
- change @Nullable CallControl to @NonNull

Impl changes:
- remove ClientTransactionalWrapper from the hidden contructor
- remove PhoneAccountHandle from the hidden constructor
- remove the if serviceInterface != null clause

Fixes: 320507724
Test: adjusted CallControlTest class
Change-Id: I7c2352ca2038c2d3d175f7ca7167d4b3b4ff340e