[Variant] Add `variant_to_arrow` `Struct` type support

[sdf-jkl]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.

Going back to #8477 I wanted to create sub issues to track state of each non-primitive type that still needs to be supported.

variant_to_arrow Struct support can improve readability and make variant_get VariantPathElement::Field implementation more straightforward.

Describe the solution you'd like

Add variant_to_arrow Struct type support

Describe alternatives you've considered

Additional context

[sdf-jkl]

take

[alamb]

label_issue.py automatically added labels {'parquet-variant'} from #9572