Fix N+1 problems in Groups API

What does this MR do and why?

Contributes to #443311 (closed)

Problem

We have a N+1 problems for several relations in Groups API. That leads to unnecessary queries and has a negative impact on the performance.

Solution

Preload relations to improve the peformance.

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

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Before	After

How to set up and validate locally

1. Use performance bar to fetch http://gdk.test:3000/api/v4/groups
2. Check results