Unable to clone from mirrors using HTTP without global permissions

Issue Summary

Users without global permissions (system admin or admin) are unable to clone from mirror using HTTP URL, if the mirror is setup without context path e.g. https://mirror.example.com (instead of https://mirror.example.com/mirror). The other read-only SCM operations (e.g. git ls-remote) also have same behaviour however the git push works fine.

This is reproducible on Data Center: yes

Steps to Reproduce

1. Setup primary and mirror Bitbucket instance using the affected versions.
2. Setup a project on mirror which has at least one repository.
3. Create a user and assign only repository admin to this user on a repository.
4. Try to clone the above repository using the above user credentials.

Expected Results

The repository is cloned successfully

Actual Results

The clone fails with the following error:

fatal: remote error: Repository not found
The requested repository does not exist, or you do not have permission to
access it.

Workaround

Use SSH URL (if SSH access enabled for the instance) to clone from the mirror.