bitbucket: Fix request to get next page of buggy page

The bitbucket Web API to list repositories has buggy pages that needs to be skipped to continue the listing.

Previously the request to get the next page when a buggy page is detected was missing the after query parameter so the request was always returning the second page of repositories listing endpoint.

Also refine buggy page detection by considering all HTTP status code >= 500.

This will unstuck the bitbucket lister in production as currently repositories created after 2022-04-22T23:42:06.051796+00:00 have not been listed.

Fixes SWH-LISTER-G1.