Description of problem:
Some web servers are configured to redirect on a 404 error while requesting .treeinfo or treeinfo files. Pulp3 expects a file or a 404 error and complains if it is something else:

Katello::Errors::Pulp3Error: Treeinfo file should have INI format

Although it's not a pulp3 fault. As it was described in https://bugzilla.redhat.com/show_bug.cgi?id=2046195#c1 such web servers are misconfigured. However, we should have an option to ignore such replies or all malformed treeinfo files to continue syncing such repositories.

See more details in the BZ mentioned above.