### Godot version

v4.0.beta15.official [4fa6edc88]

### System information

Windows 11

### Issue description

When drawing a polygon in the editor, several duplicate vertices are added to the polygon array for each click.  In the image below, I clicked three times to draw the triangle, but got 10 entries.  The number you get varies, though I don't know why; I've seen hundreds of points from drawing a hexagon.  I tested it with a Polygon2D, a CollisionPolygon2D, and a CollisionPolygon3D; the issues occurs with all of them.  It later occurred to me that this might happen with a Curve2D as well, and it does.

![image](https://user-images.githubusercontent.com/2808851/214926182-b8609b87-85a1-4a08-8017-be4eeec912c6.png)


### Steps to reproduce

Add a node that has a Polygon or Curve resource, such as a Polygon2D, draw some points, then check the PackedVector2Array resource.

### Minimal reproduction project

N/A
if (p_error) {
		switch (p_error) {
			case ERR_CANT_OPEN: {
				show_accept(vformat(TTR("Can't open file '%s'. The file could have been moved or deleted."), p_file.get_file()), TTR("OK"));
			} break;
			case ERR_PARSE_ERROR: {
				show_accept(vformat(TTR("Error while parsing file '%s'."), p_file.get_file()), TTR("OK"));
			} break;
			case ERR_FILE_CORRUPT: {
				show_accept(vformat(TTR("Scene file '%s' appears to be invalid/corrupt."), p_file.get_file()), TTR("OK"));
			} break;
			case ERR_FILE_NOT_FOUND: {
				show_accept(vformat(TTR("Missing file '%s' or one its dependencies."), p_file.get_file()), TTR("OK"));
			} break;
			default: {
				show_accept(vformat(TTR("Error while loading file '%s'."), p_file.get_file()), TTR("OK"));
			} break;
		}
	}
}
void EditorNode::_get_scene_metadata(const String &p_file) {