[substrait] [sqllogictest] GroupingSet CUBE is not yet supported

[gabotechs]

Describe the bug

~8 sqllogictest cases are failing in Substrait round-trip mode because of the following error:

query failed: DataFusion error: This feature is not implemented: GroupingSet CUBE is not yet supported

To Reproduce

cargo test --test sqllogictests -- --substrait-round-trip grouping.slt:52

Expected behavior

The sqllogictest passes in Substrait round-trip mode

Additional context

This is part of a broader initiative to improve the reliability of Substrait-to-DataFusion logical plan conversions.

• [Epic] A collection of Substrait conversion issues #16248