Add unit tests for OwR AoA Measurement.

Follow up CL to ag/20240601. Adding unit tests for these classes:
- UwbSessionManager
- UwbSessionNotificationManager

Add some validity checks to UwbSessionManager (verified with the new unit
tests).

Test: atest
Bug: 246678053
Change-Id: I06a8da1c4fbe46eaf6d674c9ec12aceafadbfa8f
7 files changed