MergeRequests::CreateService#after_create runs in the request where an MR is created. MergeRequests::AfterCreateService runs in Sidekiq after an MR is created. Ideally, the former would be empty - or limited to things that are _essential_ to happen in the creation HTTP request. In https://gitlab.com/gitlab-org/gitlab/-/merge_requests/26172 I moved pipeline creation to Sidekiq, but I left the remaining items. We should check those and move them if possible.