Since Add temporary user support to most API modules, most Wikibase editing APIs automatically create a test user and return its name; however, they don’t call the TempUserCreatedRedirect hook, and so the temporary user has no chance to be persisted in CentralAuth and will soon be lost. We should return a redirect URL in the API result; the trait ApiCreateTempUserTrait from MediaWiki core can be used to get the redirect URL and add the related API parameters.
This means that every affected API will gain three parameters: returnto, returntoquery, and returntoanchor.
