[FEATURE]: Show an alert when user tries to delete or edit a show with tickets sold

[dgurns]

Is your feature request related to a problem? Please describe.
If a user is editing or deleting a show, but tickets have been already sold, they should be warned about it.

Describe the solution you'd like

• When clicking "Edit" or "Delete" on a show with tickets attached, show a confirm dialog warning the user.

Describe alternatives you've considered

• Eventually, would be good to add a related option to refund all tickets to a show if you are going to delete it.

Additional context