Feature | Extend Swagger Coverage for controller OAuth2SummitNotificationsApiController (#418)

* feat: Add openapi documentation for OAuth2SummitNotificationsApiController

* chore: include PR requested changes

* chore: Add missing doc on public endpoint

* chore: include PR requested changes

* chore: remove repeated security schema and minor issue with operationId

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Co-authored-by: Matias Perrone <github@matiasperrone.com>

Author: andrestejerina97