Clean up redundant tests around reconcilation in request specs for the SeatLinksController

Problem

During a review of a refactor for the request specs for the SeatLinksController, the context around reconciliations in the specs was identified to not be needed in the request specs. The reconciliation logic does not impact the outcome of the requests specs. These specs should rather live in the services specs (in Utilization::CreateSubscriptionSeatLinkService and more detailed testing in CreateReconciliationService).

Proposal

Remove reconciliation related specs from spec/requests/api/v1/seat_links_request_spec.rb and ensure sufficient test coverage exists in Utilization::CreateSubscriptionSeatLinkService and CreateReconciliationService.

Result

Focus on the outcome instead of testing too many details in the requests specs.