Find an alternative to our CI code coverage action that doesn't hang / spang and freeze on upload

[darach]

Describe the problem you are trying to solve

We waste too much time and it costs focus every time we have to nurse through a PR due
to code coverage failing at upload and blocking PR throughput. The coverage UI is nice but
we would get equal value out of a GH website and static results IMO.

There must be a better way!

Describe the solution you'd like

Same coverage bar, same variance at the boundary, just a determinstic action that works without nursing!

Notes

[Licenser]

yes codecov is causing a lot of pain ...