AODTile: Explicitely disable long clicks

Returning null in the getLongClickIntent() method is not enough to disable
tile long clock and results in crashes:

  E AndroidRuntime: FATAL EXCEPTION: main
  E AndroidRuntime: Process: com.android.systemui, PID: 1391
  E AndroidRuntime: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Intent.resolveTypeIfNeeded(android.content.ContentResolver)' on a null object reference
  E AndroidRuntime: 	at android.app.ApplicationPackageManager.queryIntentActivitiesAsUser(ApplicationPackageManager.java:1062)
  E AndroidRuntime: 	at com.android.systemui.ActivityIntentHelper.getTargetActivityInfo(ActivityIntentHelper.java:70)
  E AndroidRuntime: 	at com.android.systemui.ActivityIntentHelper.wouldLaunchResolverActivity(ActivityIntentHelper.java:47)
  E AndroidRuntime: 	at com.android.systemui.statusbar.phone.StatusBar.startActivityDismissingKeyguard(StatusBar.java:2724)
  E AndroidRuntime: 	at com.android.systemui.statusbar.phone.StatusBar.startActivityDismissingKeyguard(StatusBar.java:2709)
  E AndroidRuntime: 	at com.android.systemui.statusbar.phone.StatusBar.startActivityDismissingKeyguard(StatusBar.java:2716)
  E AndroidRuntime: 	at com.android.systemui.statusbar.phone.StatusBar.handleStartActivityDismissingKeyguard(StatusBar.java:3159)
  E AndroidRuntime: 	at com.android.systemui.statusbar.phone.StatusBar.lambda$postStartActivityDismissingKeyguard$26$StatusBar(StatusBar.java:3155)
  E AndroidRuntime: 	at com.android.systemui.statusbar.phone.-$$Lambda$StatusBar$CSd9n4rtnrfFyOdT2eTFRNUO5xM.run(Unknown Source:4)
  E AndroidRuntime: 	at android.os.Handler.handleCallback(Handler.java:883)
  E AndroidRuntime: 	at android.os.Handler.dispatchMessage(Handler.java:100)
  E AndroidRuntime: 	at android.os.Looper.loop(Looper.java:214)
  E AndroidRuntime: 	at android.app.ActivityThread.main(ActivityThread.java:7356)
  E AndroidRuntime: 	at java.lang.reflect.Method.invoke(Native Method)
  E AndroidRuntime: 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:491)
  E AndroidRuntime: 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)

Change-Id: Ia7d4da4723600c47bedbfeb4b9152924a50d52dd