Description of problem:
In 6.15.0 we are not able to sync library/busybox from mirror.gcr.io
The same works well in 6.14.1 (python39-pulpcore-3.22.19-1.el8pc.noarch.rpm, python39-pulp-container-2.14.7-1.el8pc.noarch.rpm) and earlier.

Version-Release number of selected component (if applicable):
6.15.0 (python3.11-pulpcore-3.39.2-2.el8pc.noarch.rpm, python3.11-pulp-container-2.16.2-2.el8pc.noarch.rpm)

How reproducible:
always

Steps to Reproduce:
1. Create a docker repo and try to sync library/busybox from mirror.gcr.io

Actual results:
Sync task fails with
404, message='Not Found', url=URL('https://mirror.gcr.io/v2/library/busybox/manifests/1.24')

even though the URL is available and serves a schema 1 manifest

Expected results:
Successful sync