Shared calendars should allow adding attendees even if the calendar is not yours (make it a selectable option!)

[nano13]

Is your feature request related to a problem? Please describe.

The "fix" #5450 has broken a very important functionality. See the comments there for more details!

Describe the solution you'd like

Please add this feature back by implementing it properly:

• make this an option per calendar to decide if the owner wants to allow not just editing, but also others to invite people
• if other users are allowed to invite, of course that needs to trigger the invited people to get an actual invitation
• the invitation should show who actually invited them and also whom the cal belongs to

Describe alternatives you've considered

No response

Additional context

No response

[kesselb]

#5674 (comment)