Focus becomes trapped within iframe in GridListItem

^{Originally posted by **AlexGalays** July 12, 2023}
It doesn't seem possible as this hook uses `getFocusableTreeWalker` internally, which has a hardcoded list of focusable elements to cycle.

My use case: In my grid row cell, there is an iframe for read only but important purposes, so it can not be hidden. I want to skip it entirely and just go to the next item. Also currently, once the iframe has focus, it then eats all subsequent left/right arrow keyboard events, ending the navigation.

Being able to pass some `accept(node: Element) => boolean` function like in `FocusManager` might be nice?