Only refresh DISABLED_NO_THUMBNAIL when thumbnail changes

- Avoid refreshing all overlay content which happens too frequently

Bug: 193125090
Test: atest NexusLauncherTests:com.android.quickstep.TaplTestsQuickstep#testOverviewActions
Change-Id: Idcfe19a518e621c55574baae3bbe1378b7f3d08f
2 files changed