Preventing Polygon Self-Intersection with Select Mode about terra-draw HOT 3 CLOSED

This is a great idea.

I think this could be achieved by editing the onDrag event for select mode to do something to what we do with onClick in polygon mode here:

https://github.com/JamesLMilner/terra-draw/blob/main/src/modes/polygon/polygon.mode.ts#L387

You may need to update DragCoordinateBehavior to do a check using the selfIntersect function, probably changing the API schema for drag to something like this:

	public drag(event: TerraDrawMouseEvent, allowSelfIntersection: boolean): boolean {

Then checking the update geometry returns false before we do the update (otherwise just early returning like we do for coordinates that are out of bounds). You'l have to wrap the updated geometry in a Feature as the selfIntersects takes a Feature type. It would probably end up something like this:

if (geometry.type !== 'Point' && !allowSelfIntersection && selfIntersects({ type: "Feature", geometry, properties: {}})) {
      return false;
}

Let me know if I can help at all! If you get a chance to write tests that would be great, although not necessarily essential.

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Closed by accident as I tagged the wrong issue in #69 🤦🏻

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This is now resolved thanks to @UncatchableAlex - great work! 🎉

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