Add ability to set a custom title

[JayBox325]

What are you trying to do?

See this ticket: https://github.com/craftcms/cms/discussions/16739?notification_referrer_id=NT_kwDOAMnukbQxNDkwMTEwODcwMzoxMzIzMzgwOQ&notifications_query=is%3Aunread#discussioncomment-12267517

I'd like to be able to rename the expanded single to something else. See the ticket I logged above for details.

What's your proposed solution?

Adding the ability to add a custom title to the customise sources menu.

Additional context

No response