`Ci::Build.execute_hooks` always made Gitaly calls regardless of whether
a project had any hooks or services. Now we lazily only perform these
calls only if there are active hooks or services.

This is similar to what we did for `PostReceive` in
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/31741/diffs.

Relates to
https://gitlab.com/gitlab-com/gl-infra/infrastructure/issues/8407