Support OnPropertiesChangedListener in TestableDeviceConfig.

Handle add and remove listener methods, as well as making callbacks when
setProperty is called.

Test: atest FrameworksCoreTests:DeviceConfigTest
      atest FrameworksMockingServicesTests:TestableDeviceConfigTest
      atest FrameworksMockingServicesTests:AppCompactorTest
Bug: 128902955

Change-Id: Ie797d40604ab7fc860691ef07461aea42480cbfe