Add a QA scenario for creating an issue

What does this MR do?

This adds a QA scenario to ensure that issue creation works.

Are there points in the code the reviewer needs to double check?

I think the scenario should probably be improved in the future to set milestone, labels, assignee etc.

Does this MR meet the acceptance criteria?

• Review
  • Has been reviewed by Backend
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• End-to-end tests pass (package-qa manual pipeline job)

What are the relevant issue numbers?

Closes gitlab-qa#160 (closed).