Change UDF signature to use ColumnarValue rather than raw Arrow types

### What is the problem the feature request solves?

### Is your feature request related to a problem or challenge?

DataFusion uses `ColumnarValue` to represent Arrays and Scalars.

```rust
#[derive(Clone, Debug)]
pub enum ColumnarValue {
/// Array of values
Array(ArrayRef),
/// A single value
Scalar(ScalarValue),
}
```

Perhaps we should use this in the UDF signatures. This avoids the need to pass in row counts.

### Describe the solution you'd like

_No response_

### Describe alternatives you've considered

_No response_

### Additional context

_No response_

### Describe the potential solution

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### Additional context

_No response_