API Bug: “Node is not extensible” Error When Assigning Variable References to Supported Nodes Description:I am experiencing an issue with the Figma Plugin API when trying to assign variable references to node fills and strokes. Despite using a minimal file with supported node types (e.g., a simple rectangle), the plugin code fails with the error:"Node is not extensible; skipping variable linking for fills." and similarly for strokes. This error is triggered even though the node is not locked, is not a component, and variable linking is enabled in my file and account (I am on a Pro plan). Steps to Reproduce:1. Create a new Figma file and insert a basic shape (e.g., a rectangle).2. Define a local color style for a solid fill and create a local color variable in a variable collection with at least one mode (e.g., Light mode).3. Write a minimal plugin that:• Retrieves the local paint styles and color variables using the async APIs (e.g., getLocalPaintStylesAsync a
