New response field for external participants in Dashboards

Added

• New has_external_participant response field in the following Dashboards APIs:
  • GET /v2/metrics/webinars/{webinarId}
  • GET /v2/accounts/{accountId}/metrics/webinars/{webinarId}
  • GET /v2/metrics/webinars
  • GET /v2/accounts/{accountId}/metrics/webinars
  • GET /v2/metrics/meetings
  • GET /v2/accounts/{accountId}/metrics/meetings
  • GET /v2/accounts/{accountId}/metrics/meetings/{meetingId}
  • GET /v2/metrics/meetings/{meetingId}