fix: attendeeSeatId is not being returned on webhook response for events with seats

[Amit91848]

What does this PR do?

• Fixes attendeeSeatId is not being returned on webhook response for events with seats. #15010
• Fixes CAL-XXXX (Linear issue number - should be visible at the bottom of the GitHub issue description)

Mandatory Tasks (DO NOT REMOVE)

• I have self-reviewed the code (A decent size PR without self-review might be rejected)
• I have added a Docs issue here if this PR makes changes that would require a documentation change
• I have added or modified automated tests that prove my fix is effective or that my feature works (PRs might be rejected if logical changes are not properly tested)

[vercel]

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[graphite-app]

Graphite Automations

"Add community label" took an action on this PR • (05/23/24)

1 label was added to this PR based on Keith Williams's automation.

"Add consumer team as reviewer" took an action on this PR • (05/23/24)

1 reviewer was added to this PR based on Keith Williams's automation.

[github-actions]

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[CarinaWolli]

Thank you 🙏