Add session_params pub method to uwb_service.

session_params returns current params for the given session.
session_params will be used by the reconfigure JNI function since Java
doesn't return the whole app config params object when calling
reconfigure, and uwb service requires the whole params object to
reconfigure the params for a session.

Test: cargo test test_session_params; m; mma .;
Change-Id: I33c34182d029e8eb0f98fad06ed54a7f8d5f5fbb
3 files changed