Archive requests with an unexpected file extension without an accept: text/html header trigger 500

Summary

During gitlab-com/gl-infra/production#8732 (closed), we threw ~1K 500 errors and paged the EOC. They were mostly (all?) for the archive endpoint and the vast majority for a .yaml or .yml file extension. Looking at these requests, it seems like they work fine if the file extension is what we expect (e.g., .zip), but if you provide an unexpected file extension and no Accept header, then it triggers a 500.

Reproduction

OK

# 200
curl -v https://gitlab.com/gitlab-org/cli/-/archive/main/foo.zip

# 404
curl -v https://gitlab.com/gitlab-org/cli/-/archive/main/foo.yml -H 'Accept: text/html'

Failed

# 500
curl -v https://gitlab.com/gitlab-org/cli/-/archive/main/foo.yml

Impact

When requests are triggered with an unexpected file extension and no Accept header, our backend returns a 500 and enough of these errors trigger unnecessary pages for the EOC (e.g., as it happened in gitlab-com/gl-infra/production#8732 (closed)).

Recommendation

We shouldn't be throwing 500s when an unexpected file extension is requested and no Accept header.

Verification

Ensure that requests for the archive endpoint that have unexpected file extensions do not trigger a 500 error irrespective of the presence of the Accept header.