fix: added missing eqNullSafe column method

[eredzik]

Added eqNullSafe method on column (pyspark docs on this method)

[eakmanrq]

Thanks for the contribution @eredzik!

Three requests:

• Run make style and fix the issues that are currently causing the checks to be red
• Can you add a test to this file: https://github.com/eakmanrq/sqlframe/blob/a344edafa43ec9d6c3ca799f3f3902eea85200a5/tests/integration/engines/test_engine_column.py#L16-L15
  • Ideally you would cover the examples from here: https://spark.apache.org/docs/latest/api/python/reference/pyspark.sql/api/pyspark.sql.Column.eqNullSafe.html
  • This is done to check how well this works across engines. We want to confirm each engine supports it and has the same behavior of Spark.
• For each engine that supports this, add it to the supported methods for that engine (BigQuery example location here: https://github.com/eakmanrq/sqlframe/blob/df6e6da21c10952879b7ad5c3213496d98cf0bf1/docs/bigquery.md#column-class)

Let me know if this is asking too much and then I could try to get this across the finish line when I have time.

[eakmanrq]

Thanks @eredzik for following up! I think there might be a transient error with DuckDB and the Delta extension so I will see if this clears up and if not I will look to fix it in another PR and then get this in.