libaudiohal@aidl: Screen state and rotation parameters, p. II

aosp/2603929 lacks the actual code for parsing the parameters.
This was not discovered because the test was not in TEST_MAPPING.
This CL fixes both issues.

Bug: 280527932
Test: atest CoreAudioHalAidlTest
Change-Id: Ic42765710f0f1482786b2a0b7feed097206edbeb