AudioService: use AudioSystem adapter for more methods

Use AudioSystem adapter class in AudioService for:
 setPhoneState
 setAllowedCapturePolicy
 isStreamActive
 isStreamActiveRemotely
 setForceUse
 getForceUse
 registerPolicyMixes
 removeUidDeviceAffinities
 setUidDeviceAffinities
 removeUserIdDeviceAffinities
 setUserIdDeviceAffinities
 getDevicesForStream
 getDevicesForAttributes
Remove some unnecessarily nested ifs.

Bug: 162448412
Test: atest AudioServiceHostTest#testPreferredDeviceRouting
Test: atest AudioServiceHostTest#testDevicesForAttributes
Change-Id: Ifea4e29fd6971dfd921b1c87daba795a6a135199