Revert "Nullability Annotations replacement"

This reverts commit cf0501e4d7.

Reason for revert: b/317462033, it seems a flaky but revert it first.

Change-Id: Ie1d5e279cca6477fc17d8c27c1ecda8d7a6b2553

src/com/android/settings/TouchBlockingFrameLayout.java

@@ -16,13 +16,12 @@
 
 package com.android.settings;
 
+import android.annotation.Nullable;
 import android.content.Context;
 import android.util.AttributeSet;
 import android.view.MotionEvent;
 import android.widget.FrameLayout;
 
-import androidx.annotation.Nullable;
-
 /**
  * Extension of FrameLayout that consumes all touch events.
  */