fix: Let's Encrypt integration with /* redirects

Let's Encrypt integration relies on acme challenges being redirected
to main GitLab server and served there.

We also allow serving ACME challenges from project content
just in case users implemented Let's Encrypt integration manually.

But when user adds `/* -> redirect_url` to .redirects, it treated
as project content and will handles as redirect.

Changelog: fixed

This commit just stop handling redirects for any LE challenges.