This PR adds support for BOOKING_NO_SHOW_UPDATED, AFTER_HOSTS_CAL_VIDEO_NO_SHOW, and AFTER_GUESTS_CAL_VIDEO_NO_SHOW events to the Zapier integration.

/claim #18992

What does this PR do?

• Adds “No-show” triggers to the Zapier integration.
• Enrichment: Updates listBookings to include noShowHost and attendee noShow fields, allowing Zapier to access this data for setup and mapping.
• Refactor: Introduces a shared utility getFlattenedZapierPayload to ensure consistent, flattened data structures across all Zapier delivery methods (direct and scheduled).
• Consistency: Fixes a gap where non-scheduled webhooks were not correctly flattened for Zapier.
• Fixes #18992
• Fixes CAL-5107

Visual Demo (JSON proof)

Captured from the verification suite (vitest) to prove correct attribute mapping and flattening:

Zapier Setup Sample (listBookings)

```json
{
  "id": 123,
  "title": "Meeting with Ankit",
  "noShowHost": true,
  "attendees": [
    {
      "email": "test@example.com",
      "noShow": true
    }
  ]
}

Zapier Trigger Payload (‘Flattened Webhook’)

{
  "triggerEvent": "BOOKING_NO_SHOW_UPDATED",
  "createdAt": "2026-02-12T00:00:00Z",
  "bookingUid": "uid-123",
  "bookingId": 123,
  "message": "Host marked as no-show",
  "attendees": [{"email": "test@example.com", "noShow": true}]
}

How should this be tested?

1. Zapier Setup: Verify “Booking No-Show” appears in the Trigger Event list for the Cal.com Zapier app.
2. Mapping: Run a “Test trigger” and verify that the noShowHost and attendees no-show status are present in the sample data.
3. Real-time Event: Mark a meeting as a no-show and verify Zapier receives the flattened payload correctly.