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

src/com/android/settings/accessibility/HapticFeedbackIntensityPreferenceController.java

@@ -37,12 +37,6 @@ public class HapticFeedbackIntensityPreferenceController
                     VibrationAttributes.USAGE_TOUCH);
         }
 
-        @Override
-        public boolean isRestrictedByRingerModeSilent() {
-            // Touch feedback is disabled when the phone is in silent mode.
-            return true;
-        }
-
         @Override
         public int readIntensity() {
             final int hapticFeedbackEnabled = Settings.System.getInt(mContentResolver,