function pickMetadataAt(scene, schemaId, className, propertyName, x, y) {
  const screenX = Math.floor(x * canvasScaling + canvasScaling / 2);
  const screenY = Math.floor(y * canvasScaling + canvasScaling / 2);
  const screenPosition = new Cartesian2(screenX, screenY);
  const metadataValue = scene.pickMetadata(
    screenPosition,
    schemaId,
    className,
    propertyName,
  );
  return metadataValue;
}
Pick the specified metadata value from the screen that is contained in
the property texture at the given coordinates.

(This assumes that the property texture is on a unit square, and
fitCameraToUnitSquare was called)

@param {Scene} scene The scene
@param {string|undefined} schemaId The schema ID
@param {string} className The class name
@param {string} propertyName The property name
@param {number} x The x-coordinate in the texture
@param {number} y The y-coordinate in the texture
@returns The metadata value