rooms availability displays slots blocked by room twice

Steps to reproduce

1. Have a room

   • For example by creating it through:

     php occ calendar-resource:building:create \
       --address="Testweg 23, 12345 Berlin, Germany" \
       "Berlin office"
     
     php occ calendar-resource:story:create 1 "Second floor"
     
     php occ calendar-resource:room:create \
       --wheelchair-accessible=1 \
       --capacity=25 \
       --room-number=201 \
       --contact-person-user-id="demouser" \
       1 \
       "berlin-office-room-201" \
       "Meeting room 201" \
       "room.berlin.office.201@example.invalid" \
       "Meeting room"
     

2. Create event A with the room "room.berlin.office.201@example.invalid" as attendee
3. Start creating event B
4. Search for a room
5. Check the availability for "Meeting room 201"

Expected behavior

• Blocker for event A is shown once.
• Blocker for event A does not have the name "undefined".
  • I'm not sure what the expected behavior for the title is. I can think of:
    • Never show it (seem simplest solution)
    • Show it, if user has access to the event/is a participant.

Actual behavior

Calendar app version

6.5.2

CalDAV-clients used

No response

Browser

No response

Client operating system

No response

Server operating system

No response

Web server

None

Database engine version

None

PHP engine version

None

Nextcloud version

No response

Updated from an older installed version or fresh install

None

List of activated apps

Nextcloud configuration

Web server error log

Log file

Browser log

Additional info

Either freeBusyResourceEventSource or freeBusyBlockedForAllEventSource seems redundant.

			return [
				freeBusyResourceEventSource(
					this.uniqueComponentId,
					this.organizer.attendeeProperty,
					this.attendees.map((a) => a.attendeeProperty),
				),
				....
				freeBusyBlockedForAllEventSource(
					this.organizer.attendeeProperty,
					this.attendees.map((a) => a.attendeeProperty),
					this.resources,
				),
			]

freeBusyResourceEventSource seems produces the blue block with name "undefined".
freeBusyBlockedForAllEventSource produces the grey block.

Intention of freeBusyResourceEventSource might have been to display time of the actual attendees (and not the selected resources).

Reproduce the room availability search using the provided occ commands, then trace the event-source construction around freeBusyResourceEventSource and freeBusyBlockedForAllEventSource. Determine why the same blocker is rendered twice and why one shows "undefined"; done means event A appears once with an appropriate title or no title, with the relevant availability behavior covered by the existing tests.