[css-view-transitions-2] Difficult to activate view transitions as a response to UI events

[noamr]

Some UI events, such as checkbox/select change events and popover beforetoggle events have a synchronous effect on rendering. For example, a popover is closed immediately after beforetoggle, and before the rendering update occurs, which makes it tricky/impossible to fit in a startViewTransition between them.

This is also related to #9400, where the framework internal workings are not built to wait until a frame is ready before changing a state.

This can perhaps be some CSS property thing that defers the reaction to a UI event by one frame?