[SPARK-53317] Add SparkSession::create_dataframe_from_polars()

[rafafrdz]

Summary

• Add SparkSession::create_dataframe_from_polars() behind #[cfg(feature = "polars")]
• Converts Polars DataFrame to Arrow RecordBatch using polars-arrow arrow_rs interop
• Delegates to existing create_dataframe(&RecordBatch)
• No new dependencies needed — uses existing polars-arrow with arrow_rs feature

Test plan

• cargo build --features polars passes
• cargo fmt -- --check passes
• Integration test creating Spark DF from Polars DF