[validation] DataFusion #23127 targeted tests

[StealthEyeLLC]

Temporary draft PR used only to run targeted GitHub Actions validation for apache#23405. It will be closed after the checks are inspected.

[gemini-code-assist]

Code Review

This pull request introduces dynamic dictionary key promotion for group-by aggregation. When the number of distinct groups exceeds the capacity of the current dictionary key type (e.g., 256 groups for UInt8), the key type is promoted to a wider type (e.g., UInt16) at runtime. To keep transport schemas stable across repartitioning and coalescing boundaries, partial aggregate batches are sliced and limited to the planned key capacity, preserving the original schema. Final aggregation then combines all groups and dynamically promotes the output key type as needed. I have no feedback to provide as there are no review comments.

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