VCS: Avoid race between VCS initial volume set and AF volume set

Synchronize set/handling/update volume methods.
Ignore AF volume set if volume already set by VCS.
Do not use getBleVolumeFromCurrentStream as the reading is unreliable
on initialization. Value can be for another device type/address/group.

Bug: 382638927
Bug: 381507732
Test: atest VolumeControlServiceTest
Change-Id: Ic7fd250abcad11b961e1e50e4ad5100371eff8b7