Support array and map argument in array_aggregate

[thirtiseven]

Fixes #15147.

Description

This PR adds array and map type support in array_aggregate overrides. It has been implemented but never been enbaled in GpuOverriedes.

Also added some integration tests.

Checklists

Documentation

• Updated for new or modified user-facing features or behaviors
• No user-facing change

Testing

• Added or modified tests to cover new code paths
• Covered by existing tests
  (Please provide the names of the existing tests in the PR description.)
• Not required

Performance

• Tests ran and results are added in the PR description
• Issue filed with a link in the PR description
• Not required

[greptile-apps]

Greptile Summary

This PR enables ARRAY and MAP element types in the array_aggregate GPU override — support that was already implemented in GpuArrayAggregateMeta / ArrayAggregateDecomposer but was blocked by the TypeSig declaration in GpuOverrides. The docs and integration tests are updated to match.

• GpuOverrides.scala: Adds TypeSig.ARRAY and TypeSig.MAP to the argument TypeSig for ArrayAggregate, enabling inputs like ARRAY<ARRAY<...>>, ARRAY<MAP<...>>, and ARRAY<STRUCT<..., MAP/ARRAY field, ...>> to run on the GPU.
• docs/supported_ops.md: Removes ARRAY and MAP from the list of unsupported child types for this operator, consistent with the signature change.
• higher_order_functions_test.py: Adds four integration tests covering STRUCTs with nested ARRAY/MAP children, direct ARRAY-of-ARRAY and ARRAY-of-MAP inputs (parametrized), and a realistic nested filter+aggregate pattern.

Confidence Score: 5/5

Safe to merge — the change is a minimal TypeSig unlock in GpuOverrides with no modifications to the GPU execution path itself.

The TypeSig change is a single-line addition that unblocks a code path already implemented and validated by GpuArrayAggregateMeta / ArrayAggregateDecomposer. The accumulator types remain scalar-only. Four new integration tests verify GPU execution.

No files require special attention.

Important Files Changed

Filename	Overview
sql-plugin/src/main/scala/com/nvidia/spark/rapids/GpuOverrides.scala	One-line TypeSig addition — adds ARRAY and MAP to the argument nested type set.
integration_tests/src/main/python/higher_order_functions_test.py	Four new GPU-verified integration tests for the newly enabled input shapes.
docs/supported_ops.md	Removes ARRAY and MAP from unsupported child-type list, consistent with TypeSig change.

_{Reviews (2): Last reviewed commit: "add test coverage" | Re-trigger Greptile}

[thirtiseven]

build