Unused routes in workhorse

Within the workhorse routes a ciAPIPattern is being defined which is not in use any more.

As far as i understood we do not support the /ci/api any more so I think the routes using the ciAPIPattern should be removed. The following lines should be removed:

https://gitlab.com/gitlab-org/gitlab/-/blob/master/workhorse/internal/upstream/routes.go#L50:

ciAPIPattern         = `^/ci/api/`

https://gitlab.com/gitlab-org/gitlab/-/blob/master/workhorse/internal/upstream/routes.go#L249:

u.route("POST", ciAPIPattern+`v1/builds/[0-9]+/artifacts\z`, contentEncodingHandler(upload.Artifacts(api, signingProxy, preparer))),

https://gitlab.com/gitlab-org/gitlab/-/blob/master/workhorse/internal/upstream/routes.go#L263:

u.route("", ciAPIPattern+`v1/builds/register.json\z`, ciAPILongPolling),

https://gitlab.com/gitlab-org/gitlab/-/blob/master/workhorse/internal/upstream/routes.go#L354:

u.route("", ciAPIPattern, proxy),