Backend: Speed improvements for quick action autocomplete endpoint
## Summary The quick action autocomplete `commands` endpoint is very slow. ## Current Behavior Per @vshushlin: - The `commands` endpoint takes up to a few seconds to load ## Relevant Controllers Per @kivikakk: - `Projects::AutocompleteSourcesController#commands` - `Groups::AutocompleteSourcesController#commands` - These belong to `feature_category :team_planning` (~"group::project management") ## Parent Issue https://gitlab.com/gitlab-org/gitlab/-/work_items/595193
task