Adapt metadata field access deprecation to accessor function

Author: halleysfifthinc

webio_jupyter_extension/webio-jupyter-labextension/labextension.ts

@@ -230,7 +230,7 @@ class WebIONotebookManager {
     if (!this.notebook.model) {
       throw new Error("Notebook model is not available!");
     }
-    return (this.notebook.model.metadata.get(WEBIO_METADATA_KEY) || {}) as any;
+    return (this.notebook.model.getMetadata(WEBIO_METADATA_KEY) || {}) as any;
   }
 
   private setWebIOMetadata(kernelId: string, commId: string) {
@@ -242,7 +242,7 @@ class WebIONotebookManager {
     if (!this.notebook.model) {
       throw new Error("Notebook model is not available!");
     }
-    this.notebook.model.metadata.set(WEBIO_METADATA_KEY, metadata as any);
+    this.notebook.model.setMetadata(WEBIO_METADATA_KEY, metadata as any);
   }
 }