[Data] Persist unresolved paths in FileBasedDataSource. (#51424)

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## Why are these changes needed?

This PR adds support for storing the original, unresolved paths in the
`FileBasedDatasource` class. This allows components to access the raw
path pattern provided by the user before any path resolution or
expansion occurs.

This also adds consistency with
[`ParquetDatasource`](https://github.com/ray-project/ray/blob/936539ce15bffa8dfa0a519fee2c7c8c0ee341b8/python/ray/data/_internal/datasource/parquet_datasource.py#L202)
and
[`_FileDatasink`](https://github.com/ray-project/ray/blob/936539ce15bffa8dfa0a519fee2c7c8c0ee341b8/python/ray/data/datasource/file_datasink.py#L66).

## Related issue number

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commit -s`) in this PR.
- [x] I've run `scripts/format.sh` to lint the changes in this PR.
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https://docs.ray.io/en/master/.
- [ ] I've added any new APIs to the API Reference. For example, if I
added a
method in Tune, I've added it in `doc/source/tune/api/` under the
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few flaky tests, see the recent failures at https://flakey-tests.ray.io/
- Testing Strategy
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Signed-off-by: Jakub Dardzinski <kuba0221@gmail.com>

Author: JDarDagran

python/ray/data/datasource/file_based_datasource.py

@@ -140,6 +140,7 @@ def __init__(
         self._partitioning = partitioning
         self._ignore_missing_paths = ignore_missing_paths
         self._include_paths = include_paths
+        self._unresolved_paths = paths
         paths, self._filesystem = _resolve_paths_and_filesystem(paths, filesystem)
         self._filesystem = RetryingPyFileSystem.wrap(
             self._filesystem, retryable_errors=self._data_context.retried_io_errors