Monitor indexes with forbidden access

[mayaCostantini]

Is your feature request related to a problem? Please describe.

Related to https://github.com/thoth-station/solver/issues/5221 Register a Prometheus metric to monitor indexes sending back a 403 error when trying to get packages

Describe the solution you'd like

Push the metric to Prometheus right before the Exception is raised to have it available in a Graphana dashboard

[mayaCostantini]

/sig devsecops /priority important-soon

[sesheta]

Issues go stale after 90d of inactivity. Mark the issue as fresh with /remove-lifecycle stale. Stale issues rot after an additional 30d of inactivity and eventually close.

If this issue is safe to close now please do so with /close.

/lifecycle stale

[harshad16]

/remove-lifecycle stale /lifecycle frozen