Null check overlayPaths/resourceDirs when applying widget changes

It's possible a previous snapshot change altered the nullability
of these values, but the String[] for both resourcesDirs and
overlayPaths are expected to be nullable anyways, so just null
check them before cloning.

Bug: 216722631

Test: atest com.android.cts.webkit.WebViewHostSideMultipleProfileTest#testSecondProfile

Change-Id: I56aaf6d5aec1ec14bc7986fe58e1cc77cf6b8376