Make sure url bar is not focused when window is detached (#3284)

Author: keianhzo

app/src/common/shared/org/mozilla/vrbrowser/ui/views/NavigationURLBar.java

@@ -240,6 +240,7 @@ private void initialize(Context aContext) {
 
     public void detachFromWindow() {
         if (mViewModel != null) {
+            mViewModel.setIsFocused(false);
             mViewModel.getIsLoading().removeObserver(mIsLoadingObserver);
             mViewModel.getIsBookmarked().removeObserver(mIsBookmarkedObserver);
             mViewModel = null;