Fix closing all modals (#12728)
* Fix closing all modals
We used `Modal.closeCurrentModal()` in a bunch of places, in all cases
(as far as I can see: it wasn't commented) we meant to close all open
modals. This swaps that function for one that closes all open modals.
Also types the close reason which claimed to be something in a comment,
of course, was wrong because a load of places passed their own random
string which was never used.
* Force close modals
* Try with minimal changes
* Already had a method for this
* Add test
* More tests
* Unused importsd
