Don't remove dev deps just because they're also configured as pre-commit hooks #1126

For example, currently Ruff is being removed as a dev dep when running usethis tool pre-commit.

When using uv and hence sync-with-uv, there's absolutely no need.

If using a None backend, we don't touch dev deps anyway.

For a future backend, hopefully we'll have another sync tool.

Make sure to test this case.