Revert `license` and `license-files` changes in `pyproject.toml` (#19624)
Summary
--
This partially reverts commit 13634ff433310fa4b718c57cb8ea43ab334e2637
after issues in the release today.
Test Plan
--
```shell
uv build --sdist
tar -tzf dist/ruff-0.12.6.tar.gz | grep ruff-0.12.6/LICENSE
```
which finds the license now.