This PR short-circuits `Response::interact()` when the `Response` has
already been sufficiently "sensed" already. In some circumstance, this
can avoid unnecessarily registering another widget rect that may mask
some other widget.
One such instance is Rerun's `ListItem`. Calling `context_menu()` on its
response would call `interact` and, in turn, mask its sub-widget
(collapsing triangle, show/hide buttons, etc.).
0e1bcc2c1c