VolumeControlService: Fix update volume during ringtone

When remote updates a volume during ringtone, we should not apply this
volume to the STREAM_MUSIC.
Instead we read it as an intetion to use this volume for the
STREAM_VOICE_CALL.

Bug: 323110164
Bug: 324041939
Test: atest VolumeControlServiceTest
Change-Id: Ic6a8518a2f3dedbd75e808048a31b033fd5b9f86