## #22661
- Update `FlashMessage` behavior to, by default, hide itself when the
user performs any URL-changing navigation
- Add `persistOnPageChange` option to `renderFlash` API and associated
notification context and reducer logic, allowing override of this
behavior on a per-call basis
- Ensure proper order of evaluation of URL changes and render flash
action dispatches on the event loop
- Clean up legacy unused "undo"-related arguments and logic
- Allow the user to click in the same horizontal dimension as a flash
message
- Other misc. cleanup and refactoring
[Demo - messages hidden on page (any URL)
change](https://www.loom.com/share/1e884b6ba11c4b59bc74f51df3690131?sid=9b53e78b-6535-4541-b676-377760366cf4)
- [x] Changes file added for user-visible changes in `changes/`,
- [x] Manual QA for all new/changed functionality
---------
Co-authored-by: Jacob Shandling <jacob@fleetdm.com>
