Add mStatusBarWindowController null check on ACTION_SCREEN_OFF

Bug: 117401888
Test: Builds and manual verification
Change-Id: Id4e000588ad3dae97ed519da6d23b2c9a639cf0e
(cherry picked from commit 0cfa37911dd384a03bda3ac7e27f8196b153c54b)
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/phone/StatusBar.java b/packages/SystemUI/src/com/android/systemui/statusbar/phone/StatusBar.java
index 90ed97f..a7c43cd 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/phone/StatusBar.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/StatusBar.java
@@ -2852,7 +2852,9 @@
                 }
             }
             else if (Intent.ACTION_SCREEN_OFF.equals(action)) {
-                mStatusBarWindowController.setNotTouchable(false);
+                if (mStatusBarWindowController != null) {
+                    mStatusBarWindowController.setNotTouchable(false);
+                }
                 finishBarAnimations();
                 resetUserExpandedStates();
             }