Remove temporary dead_code allowance from sedona-raster-gdal gdal_common and gdal_dataset_provider

## Summary
`rust/sedona-raster-gdal/src/lib.rs` currently keeps `mod gdal_common;` and `mod gdal_dataset_provider` behind `#[allow(dead_code)]` because there are no GDAL based RS functions to use then yet.

## Why
This is a temporary lint suppression and should be removed once the crate has a real internal or public use. Examples usages are in this WIP PR about GDAL-based RS functions: https://github.com/apache/sedona-db/pull/704

Open rust/sedona-raster-gdal/src/lib.rs and inspect the declarations for gdal_common and gdal_dataset_provider. Review the example usages in WIP PR #704 to confirm the modules now have internal or public use, then remove the temporary dead_code allowance and run the relevant Rust checks to verify the lint passes.

Written by the indexing model from the issue text.