[VL] Spark 4.x: Support Variant type

### Description

Spark-4.0 has added new data type `VariantType`. The support for VariantType and variant shredded data has been added to parquet reader and writer.

Refer:
- https://issues.apache.org/jira/browse/SPARK-50614
- [[SPARK-48495](https://issues.apache.org/jira/browse/SPARK-48495)][SQL][DOCS] Describe shredding scheme for Variant
- [[SPARK-50614](https://issues.apache.org/jira/browse/SPARK-50614)][SQL] Add Variant shredding support for Parquet
- [[SPARK-54454](https://issues.apache.org/jira/browse/SPARK-54454)][SQL] Enable variant shredding and variant logical type annotation configs by default

This feature has been enabled by default in Spark. Currently, since Gluten does not support `VariantType`, need to add fallback.

### Gluten version

None