Revert "Remove duplicate warning for settings discovery errors (#7384)" (#7594)
## Summary
This reverts commit 3060fd22c00c3f5ca96374747600c8b4bab6a896.
These are now _never_ shown to users, because `tracing` isn't set up at
that point. I'm going to try and improve the solution more holistically,
but this is better than the status quo.
Closes https://github.com/astral-sh/uv/issues/7573.