Cache results of isLocationEnabledForUser calls

This reduces number of Binder calls that Bluetooth stack is making while
scanning in a noisy environments.

Currently we make one call for each scan result. After this patch, the
result is cached for two seconds.

Test: observe result of "adb shell dumpsys binder_calls_stats" during
      scan.
Bug: 125739276
Change-Id: I777417de356c323b8ea5bebfd1b0a29c27730b13