Remove Warning/Error messages when using `build`

[LecrisUT]

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Basically when running python3 -m build on a perfectly valid project, we find ourselves surprised by unnecessary warning and error messages, namely:

UserWarning: git archive did not support describe output
UserWarning: unprocessed git archival found (no export subst applied)
ERROR setuptools_scm._file_finders.git listing git files failed - pretending there aren't any

See the linked issue for more context on why these messages occur. This PR is trying to eliminate those messages, but first I am writing a test to reproduce a common environment. Thanks to @Mr0grog for the help debugging this issue

TODO:

• [x] Add test to check build messages
• [ ] Resolve the git_archival.txt warning issue
• [ ] Resolve the setuptools_scm._file_finders.git error issue

Closes #987