Get undone revision id from hook param instead of request
Get undone revision id from hook param instead of request

The PageContentSaveComplete hook is now inside a deferred update, so
when using the API, 'wpUndidRevision' is no longer present in the
request. This gets the undone rev id from a new param added to the hook.

Bug: T153567
Change-Id: Id539a7db8d8f5e902177845bd212b4d6c2500f89
Depends-On: I50dcb841cd0616acc2d69c3a685ba3cb339986c3

wikimedia/mediawiki-extensions-Echo,wikimedia/mediawiki-extensions-Echo,wikimedia/mediawiki-extensions-Echo,wikimedia/mediawiki-extensions-Echo