meta: Remove black GH action

[sl0thentr0py]

Since we moved to pre-commit in #1315 anyway, we don't need this flaky black stuff to run on push.
The lint step checks with black --check either way.

[BYK]

@sl0thentr0py you still need someone with repo admin access to remove that required format check in branch protection rules.

[antonpirker]

I am also for removing it.

One thing we might keep in mind: people submitting PRs maybe do not have pre-commit installed so can submit horribly formatted code.

[sl0thentr0py]

I wanted to bring this up in the pre-commit PR but anyway, let's do it now.
We already have make format here, now that we added pre-commit, that's redundant.
I initially thought why add a new tool when we can just run make format in a simple git pre-commit hook?
But anyway, now that we added it, we can just change the Makefile and make users setup pre-commit in CONTRIBUTING.md.

[BYK]

One thing we might keep in mind: people submitting PRs maybe do not have pre-commit installed so can submit horribly formatted code.

@antonpirker I tried that, your linter yells at me so nothing to worry about 🤣