fix: update transfer function points in JSON in all cases (#594)

src/webgl/shader_ui_controls.ts

@@ -1155,7 +1155,7 @@ export class TrackableTransferFunctionParameters extends TrackableValue<Transfer
  // to the control points in the trackable value.
  const defaultValueCopy = copyTransferFunctionParameters(defaultValue);
  super(defaultValueCopy, (obj) =>
- parseTransferFunctionParameters(obj, dataType, defaultValue),
+ parseTransferFunctionParameters(obj, dataType, defaultValueCopy),
  );
  }