ActivityBlockingActivity did not release listener after onDestroy invoked

ActivityBlockingActivity.onCreate() registered a listener into CarUxRestrictionsManagementService. But was not released after ActivityBlockingActivity.onDestroy() invoked.

Test: Enable/disable ActivityBlockingActivity rapidly
Signed-off-by: qvu <qvu.ford@gmail.com>
Change-Id: I896fad7ce06b89267520d4b369ab9c3d74fa38e7