Update the settings privacy page to the latest mocks

Add the mic and camera toggles to the page. Also create an helper class
to keep binder calls to the system_server at a minimum.

Test: make RunSettingsRoboTests
Test: atest SettingsUnitTests
Test: Manual
Bug: 183985427
Change-Id: Iff6ee1c9a2c30095307f636decbcfcf298ed31b0