Minimal Reproducible Example for a JavaFX Tables focus-within bug

The focusWithin property is not always set correctly for tables.

Instructions to reproduce:

1. Launch the given demo App
2. Notice that initial focus is in the TextField.
   • Broken: The TableView's focusWithin is true.
3. Click on any cell in the TableView to focus it and set it's selection
4. Click on the TextField to focus it.
   • Broken: The TableView's focusWithin is true.
5. Press ESCAPE to clear the TableView's selection. Now the TableView focusWithin is false. Although that is correct, it is not expected/intuitive for clearing the TableView's selection to have the side effect of changing it's focusWithin.