Reduce number of queries made by Projects::IssuesController#create_merge_request

What does this MR do?

This MR is a performance optimization for reducing the number of queries made by the controller.

For example when looking at SELECTs issued just by running a single test under the controller spec there 150 select queries made. When accounting for duplicates there are only 73 left. The idea is to optimize by checking for excessive duplicate calls and seeing whether these could be removed. See duplicate queries and unique queries.

The following optimizations have been done:

• ProjectTeam: reduce number of calls by memoizing (15 -> 2)
• License: pending
• Projects: pending

Screenshots (strongly suggested)

Does this MR meet the acceptance criteria?

Conformity

• 📋 Does this MR need a changelog?
  • I have included a changelog entry.
  • I have not included a changelog entry because _____.
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team

Related to #20815 (closed)