Projects list API - Improve pre-loader

From an examination of queries it looks like our preload queries perform the same complex subquery a number of times. The proposal is to perform the base query once and use the ID values in the preload queries rather than as a subquery.

Availability and Testing

• Consider using a feature flag with this change, which will allow us to roll out and monitor any potential issues on staging and production.
  • This would also trigger e2e:package-and-test with ee:instance-parallel and ee:instance-parallel-ff-inverse jobs on the MR for functional regression tests.
  • If a feature flag cannot be used, and changes don't trigger a review app pipeline, please trigger e2e:package-and-test job manually

Feel free to reach out to:

• @vburton for any questions on functional testing, QA failures, etc.
• The Quality Enablement team for running any additional performance tests needed