[fix] Use indirect writemethod for BigQuery writes to actually output partitioned tables. (#257)

… partitioned tables.

## Summary

## Checklist
- [ ] Added Unit Tests
- [ ] Covered by existing CI
- [ ] Integration tested
- [ ] Documentation update



<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **Bug Fixes**
- Improved BigQuery data writing method to support partitioned tables by
changing the write method from "direct" to "indirect".

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: david-zlai

cloud_gcp/src/main/scala/ai/chronon/integrations/cloud_gcp/GcpFormatProvider.scala

@@ -50,7 +50,7 @@ case class GcpFormatProvider(sparkSession: SparkSession) extends FormatProvider
     val sparkOptions: Map[String, String] = Map(
       // todo(tchow): No longer needed after https://github.com/GoogleCloudDataproc/spark-bigquery-connector/pull/1320
       "temporaryGcsBucket" -> sparkSession.conf.get("spark.chronon.table.gcs.temporary_gcs_bucket"),
-      "writeMethod" -> "direct",
+      "writeMethod" -> "indirect", // writeMethod direct does not output partitioned tables. keep as indirect.
       "materializationProject" -> tableId.getProject,
       "materializationDataset" -> tableId.getDataset
     ) ++ partitionColumnOption