Fix bug in macro average for a number of classification metrics

[SkafteNicki]

What does this PR do?

Redo of PR #1715.

Fixes #1693
Fixes #1692
Fixes #1691
Fixes #1664

This time tests should pass. There are repetitions in the introduced code that could be refactored, but lets figure that out in a follow up PR.

Before submitting

• Was this discussed/agreed via a Github issue? (no need for typos and docs improvements)
• Did you read the contributor guideline, Pull Request section?
• Did you make sure to update the docs?
• Did you write any new necessary tests?

PR review

Anyone in the community is free to review the PR once the tests have passed.
If we didn't discuss your PR in Github issues there's a high chance it will not be merged.

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Make sure you had fun coding 🙃

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📚 Documentation preview 📚: https://torchmetrics--1821.org.readthedocs.build/en/1821/

[codecov]

Codecov Report

Merging #1821 (03f0729) into master (181e112) will decrease coverage by 0%.
The diff coverage is 100%.

Additional details and impacted files

@@          Coverage Diff           @@
##           master   #1821   +/-   ##
======================================
- Coverage      87%     87%   -0%     
======================================
  Files         254     254           
  Lines       14310   14307    -3     
======================================
- Hits        12513   12510    -3     
  Misses       1797    1797