Remove storeVolumeForDevice() in AvrcpTargetService

Since AvrcpVolumeManager will store volume level for active device when
there is a volume changed from remote headset or Framework. No longer
need to store volume when switching active device. This can also prevent
storing wrong volume level for remote device.

Bug: 138772315
Bug: 139917647
Test: Switching media path between Bluetooth devices and wired headset
Change-Id: I1a8b91fb80a9e1fa56de088e66092b74e13e1888