As an organizer, I want to be redirected to the event page after enabling registration, so that I can review the updated page.
Once this work is complete, we can do T377998.
**Acceptance criteria:**
* Given an organizer has created an Event page
** When an event registration has been successfully enabled on Special:EnableEventRegistration
** Then the user should be redirected to the Event page
** And they should see a success message in a bubble notification
*** The exact content of the success message will be handled in T377998
** And if there are any warnings, they should be displayed in separate bubble notifications
Note: This work is a follow up from T333579.
**Experience that we are updating (current flow):**
{F57634630}
**Out of scope**: Special:EditEventRegistration, covered in T378768.