Only show zen rule gear if intent is valid

Test: manual
Fixes: 122638690
Change-Id: Ib9b37b2844ef7a439e38e5e71827903709fca46f

src/com/android/settings/notification/ZenRulePreference.java

@@ -171,6 +171,9 @@ public class ZenRulePreference extends TwoTargetPreference {
                 getSettingsActivity(rule, si);
         mIntent = AbstractZenModeAutomaticRulePreferenceController.getRuleIntent(action,
                 settingsActivity, mId);
+        if (mIntent.resolveActivity(mPm) == null) {
+            mIntent = null;
+        }
         setKey(mId);
     }