A way to specify constant/scalar arguments in UDFs

[Jefffrey]

Is your feature request related to a problem or challenge?

Some UDFs may expect a constant/scalar/literal argument, and not allow array inputs.

For example, arrow_cast:

datafusion/datafusion/functions/src/core/arrow_cast.rs

Lines 134 to 148 in f27e50c

	type_arg
	.and_then(|sv| sv.try_as_str().flatten().filter(|s| !s.is_empty()))
	.map_or_else(
	|| {
	exec_err!(
	"{} requires its second argument to be a non-empty constant string",
	self.name()
	)
	},
	|casted_type| match casted_type.parse::<DataType>() {
	Ok(data_type) => Ok(Field::new(self.name(), data_type, nullable).into()),
	Err(ArrowError::ParseError(e)) => Err(exec_datafusion_err!("{e}")),
	Err(e) => Err(arrow_datafusion_err!(e)),
	},
	)

Describe the solution you'd like

Some way to specify this at the signature level instead of needing this manual handling. This can then centralize the logic across the functions that need this.

Describe alternatives you've considered

No response

Additional context

Perhaps wire it only into the coercible signatures?