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
(cherry picked from https://android-review.googlesource.com/q/commit:e92c34b099b45d5aeab40a45f0877ea7390ac469)
Merged-In: Ic42765710f0f1482786b2a0b7feed097206edbeb
Change-Id: Ic42765710f0f1482786b2a0b7feed097206edbeb