Add NPE check in CameraTransitionCallback

CameraManager.AvailabilityCallback will notifyCameraInactive()
at initial stage, and cause NPE when mCutoutViews is NULL

Initialize mCutoutView at early stage

Bug: 151706640
Test: manual boot device
Test atest SystemUITests

Change-Id: I2008342d15bb589f85bb99fcc35ede96ef9678bd

packages/SystemUI/src/com/android/systemui/ScreenDecorations.java

@@ -122,7 +122,7 @@ public class ScreenDecorations extends SystemUI implements Tunable {
     protected int mRoundedDefaultBottom;
     @VisibleForTesting
     protected View[] mOverlays;
-    private DisplayCutoutView[] mCutoutViews;
+    private DisplayCutoutView[] mCutoutViews = new DisplayCutoutView[BOUNDS_POSITION_LENGTH];
     private float mDensity;
     private WindowManager mWindowManager;
     private int mRotation;