Required changes identified in the review on T327570:
* [ ] `?!` Don't try to save preferences for temp users, if they can't have them – use cookies or local storage instead where applicable, like for logged out users
* [ ] Update code using VisualEditorDisableForAnons config option – this might be a good opportunity to reach out to the wikis using it (enwiki, eswiki, zhwiki) and figure out if it's still needed. The option doesn't actually disable the editor, but it affects edit tabs and the default editor.
* [ ] Update code that deals with refreshing session info when the user logs in / log out in another tab while editing, to also handle transitioning to/from a temp user account
* [ ] Update messages about revealing your IP address in edit notices – this might be a good opportunity to centralize our edit notice code with MediaWiki core
* [ ] Correct signature in the preview when a temp user would be created (VE, NWE)
* [x] {T332437}
** https://gerrit.wikimedia.org/r/c/schemas/event/secondary/+/907960
** https://gerrit.wikimedia.org/r/c/mediawiki/extensions/WikimediaEvents/+/907964