fix: seated booking title to show correct attendee name for attendee view

[hemantmm]

closes: #17367

What does this PR do?

API (output.service.ts)

• Personalizes title in:
  getOutputSeatedBooking
getOutputRecurringSeatedBooking
• Replaces the first attendee's name with the current attendee’s name.

Web (booking.ts):

1. Updates handleSeatsEventTypeOnBooking.
2. Replaces the first attendee's name in the title with the correct attendee’s name.
3. Keeps attendee visibility rules intact.

• Fixes [CAL-4630] Booking title for seated bookings #17367
• Fixes CAL-4630

Mandatory Tasks (DO NOT REMOVE)

• I have self-reviewed the code (A decent size PR without self-review might be rejected).
• I have updated the developer docs in /docs if this PR makes changes that would require a documentation change. If N/A, write N/A here and check the checkbox.
• I confirm automated tests are in place that prove my fix is effective or that my feature works.

[graphite-app]

Graphite Automations

"Send notification to Community team when High Priority PR opened" took an action on this PR • (02/14/26)

2 teammates were notified to this PR based on Keith Williams's automation.

[cubic-dev-ai]

No issues found across 2 files

[romitg2]

Thanks @hemantmm for PR, we'll require a visual demo for this PR, can you please add it?