## Which issue does this PR close?

- Closes #.

## What changes are included in this PR?

While reviewing #1997, i noticed a couple of improvements we can make

1. `make install` should install the local editable `pyiceberg-core` so
that i can do `make install && make test`
2. CI should fail on warnings 
3. test should not read local env files (we made a similar fix in
pyiceberg apache/iceberg-python#3006).
Otherwise, tests were reading `~/.pyiceberg.yaml` and polluting the runs

## Are these changes tested?

Yes. 

For (2), see that [it fails in
CI](https://github.com/apache/iceberg-rust/actions/runs/22410058261/job/64880767855?pr=2178)
before removing the use of deprecated `register_table_provider`