No more ever repeating tries to download errored healpix tiles

[imbasimba]

For example non existing tiles (404)

[pkgw]

CI failure use due to the fact that we have to use a custom build agent for the Windows builds:

https://docs.worldwidetelescope.org/infrastructure-guide/1/appendix-build-agent/

I'll need to rerun these steps to update the build agent.

[pkgw]

Fixed the CI issue.