Disable "double tap to check" when "always on"

"Double tap to check" has no effect when AOD is enabled.
Double tapping will take you to the lock screen anyway.

Test: manual
Test: make RunSettingsRoboTests ROBOTEST_FILTER=DoubleTapScreenPreferenceControllerTest
Change-Id: Ia97b7ecb00a9d83b867959d83642d476841e2f13
Fixes: 73096311

src/com/android/settings/gestures/DoubleTapScreenPreferenceController.java

@@ -102,4 +102,9 @@ public class DoubleTapScreenPreferenceController extends GesturePreferenceContro
         return new InlineSwitchPayload(SECURE_KEY, ResultPayload.SettingsSource.SECURE,
                 ON /* onValue */, intent, isAvailable(), ON /* defaultValue */);
     }
+
+    @Override
+    protected boolean canHandleClicks() {
+        return !mAmbientConfig.alwaysOnEnabled(mUserId);
+    }
 }