VolumeControlService: Fix setting volume on active group

Volume control service was missing information about group being active
and was no able to change the volume for the active group.

Issue could be observed after phone restart or when switching between
two LE HS

Bug: 302142886
Test: atest VolumeControlServiceTest
Tag: #feature
Change-Id: Idc11e503d2c0cea67ce0738fabde0adb0797a358