feat: Add ST_IsEmpty

[ianthetechie]

What it says on the tin :) Seemed like some low-hanging fruit.

[kylebarron]

Thanks! Can you add to register:

geodatafusion/rust/geodatafusion/src/udf/native/accessors/mod.rs

Lines 17 to 31 in 778ed43

	pub fn register(session_context: &datafusion::prelude::SessionContext) {
	session_context.register_udf(CoordDim.into());
	session_context.register_udf(NDims.into());
	session_context.register_udf(GeometryType.into());
	session_context.register_udf(ST_GeometryType.into());
	session_context.register_udf(IsClosed.into());
	session_context.register_udf(EndPoint::default().into());
	session_context.register_udf(StartPoint::default().into());
	session_context.register_udf(NPoints.into());
	session_context.register_udf(NumInteriorRings.into());
	session_context.register_udf(M::default().into());
	session_context.register_udf(X::default().into());
	session_context.register_udf(Y::default().into());
	session_context.register_udf(Z::default().into());
	}

[ianthetechie]

I thought I did... but it's also equally probable that I'm a bit dense today, or GitHub PR displays are on the fritz 😅

[kylebarron]

Oh I just noticed that file now; thanks!