Use read-write lock to guard property config.

Property config now may change dynamically due to late-init. We might
also support dynamic config later. This CL uses read write lock
to properly guard access to config map.

Flag: EXEMPT HAL change
Test: atest DefaultVehicleHalTest
Bug: 342470570
Change-Id: I0df79040c363e66baab48631f457752532d2967d