Remove date_trunc transform on a partition timestamp column in retention stmt

[teamurko]

Summary

This is an optimization change to enable predicate-pushdown in delete statement in retention job. Spark plan without the change:

scala> spark.sql("explain select count(*) from T where date_trunc('HOUR', datepartition) < date_trunc('HOUR', current_timestamp() - INTERVAL 72 HOURs)").show(2000, false)
...                                                                                                                                                                                                                                                                                                                                                                                                                                                     
|== Physical Plan ==
AdaptiveSparkPlan isFinalPlan=false
+- HashAggregate(keys=[], functions=[count(1)])
   +- Exchange SinglePartition, ENSURE_REQUIREMENTS, [id=#46]
      +- HashAggregate(keys=[], functions=[partial_count(1)])
         +- Project
            +- Filter (date_trunc(HOUR, datepartition#188, Some(UTC)) < 1716652800000000)
               +- BatchScan openhouse.T[datepartition#188] openhouse.T [filters=]

Spark plan after the change:

scala> spark.sql("explain select count(*) from T where datepartition < date_trunc('HOUR', current_timestamp() - INTERVAL 72 HOURs)").show(2000, false)
...
|== Physical Plan ==
AdaptiveSparkPlan isFinalPlan=false
+- HashAggregate(keys=[], functions=[count(1)])
   +- Exchange SinglePartition, ENSURE_REQUIREMENTS, [id=#71]
      +- HashAggregate(keys=[], functions=[partial_count(1)])
         +- Project
            +- Filter (isnotnull(datepartition#220) AND (datepartition#220 < 1716656400000000))
               +- BatchScan openhouse.T[datepartition#220] openhouse.T[filters=datepartition IS NOT NULL, datepartition < 1716656400000000]

scala> spark.sql("explain delete from T where datepartition < date_trunc('HOUR', current_timestamp() - INTERVAL 72 HOURs)").show(2000, false)
...
|== Physical Plan ==
ReplaceData IcebergBatchWrite(table=openhouse.T, format=ORC), org.apache.spark.sql.execution.datasources.v2.ExtendedDataSourceV2Strategy$$Lambda$4425/341350645@38e84b78
+- AdaptiveSparkPlan isFinalPlan=false
   +- Project [...]
      +- Sort [_file#279 ASC NULLS FIRST, _pos#280L ASC NULLS FIRST], false, 0
         +- Filter NOT ((isnotnull(datepartition#252) AND (datepartition#252 < 1716656400000000)) <=> true)
            +- ...] openhouse.T [filters=datepartition IS NOT NULL, datepartition < 1716656400000000]
               +- HashAggregate(keys=[_file#279], functions=[])
                  +- Exchange hashpartitioning(_file#279, 200), ENSURE_REQUIREMENTS, [id=#122]
                     +- HashAggregate(keys=[_file#279], functions=[])
                        +- Project [_file#279]
                           +- Filter (isnotnull(datepartition#252) AND (datepartition#252 < 1716656400000000))
                              +- ExtendedBatchScan[...] openhouse.T [filters=datepartition IS NOT NULL, datepartition < 1716656400000000]

Changes

• [ ] Client-facing API Changes
• [ ] Internal API Changes
• [ ] Bug Fixes
• [ ] New Features
• [x] Performance Improvements
• [ ] Code Style
• [ ] Refactoring
• [ ] Documentation
• [ ] Tests

For all the boxes checked, please include additional details of the changes made in this pull request.

Testing Done

• [ ] Manually Tested on local docker setup. Please include commands ran, and their output.
• [ ] Added new tests for the changes made.
• [x] Updated existing tests to reflect the changes made.
• [ ] No tests added or updated. Please explain why. If unsure, please feel free to ask for help.
• [x] Some other form of testing like staging or soak time in production. Please explain.

Ran explain on the stmt and existing tests pass.

Additional Information

• [ ] Breaking Changes
• [ ] Deprecations
• [ ] Large PR broken into smaller PRs, and PR plan linked in the description.

For all the boxes checked, include additional details of the changes made in this pull request.