Collect metrics from all pull mirrors

What does this MR do and why?

Contributes to #367846 (closed)

Problem

def mirror? includes additional checks that can exclude projects with pull mirroring enabled but without the license. But we want to collect metrics for these projects too.

Solution

Fetch mirror status directly from the project.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.