Enable touch feedback settings when the phone is in silent mode

Allow users to change this settings when the phone is in silent mode, if
they prefer to make all interactions as silent as possible in that
context.

Fix: 165478128
Test: [Alarm|HapticFeedback|Media]Vibration[Intensity|Toggle]PreferenceControllerTest
Change-Id: I68f90559b2bf8088f22397412c149e2a4b91cf13