[FEATURE REQUEST]: Support StructArray as a return type in ArrowFunctions.VectorUdf

We need to support `StructArray` as a return type in `ArrowFunctions.VectorUdf`.

To repro:
```csharp
Func udf
= ArrowFunctions.VectorUdf((Func) someUDFWrapper);
```
You will get:
```
Unhandled Exception: System.ArgumentException: Apache.Arrow.StructArray is not supported.
at Microsoft.Spark.Utils.UdfUtils.GetReturnType(Type type)
at Microsoft.Spark.Sql.Functions.CreateUdf[TResult](String name, Delegate execute, PythonEvalType evalType)
at Microsoft.Spark.Sql.ArrowFunctions.VectorUdf[T1,T2,TResult](Func`3 udf)
```