[IMPR] AudioService: improve bijectivity between VSS / VGS

Bug: 260298113

This CL improves bijectivity between VolumeStreamStates
and VolumeGroupStates.
The cache of the stream/attributes volume must by synced on
not only the values but also the muted state.

To prevent race, VSS and VGS are synchronized on the same lock
as they need to sync each others.

Test: dumpsys audio & check index aligned between stream and
associated volume group
adb shell am instrument -w -e class com.android.audiopolicytest.* com.android.audiopolicytest

Signed-off-by: Francois Gaffie <francois.gaffie@renault.com>
Change-Id: I78bfa0d1d87d90125f101bdb77e504181cc4c77e