Follow-up from "Add GraphQL mutation to create an alert issue"

The following discussion from !31820 (merged) should be addressed:

• @splattael started a discussion: (+1 comment)

  Non-blocking: Should we add an API spec as a smoke test to prevent bugs like !31525 (merged)? 🤔

  We've added some mutation API specs in !31668 (merged) in the case above.

Create an API tests for CreateAlertIssue GraphQL mutation