Make onChange optional

extensions/ql-vscode/src/view/common/Dropdown.tsx

@@ -20,7 +20,7 @@ type Props = {
   options: Array<{ value: string; label: string }>;
   disabled?: boolean;
   disabledPlaceholder?: string;
-  onChange: (event: ChangeEvent<HTMLSelectElement>) => void;
+  onChange?: (event: ChangeEvent<HTMLSelectElement>) => void;
 };
 
 /**

extensions/ql-vscode/src/view/model-editor/InProgressDropdown.tsx

@@ -2,17 +2,12 @@ import * as React from "react";
 import { Dropdown } from "../common/Dropdown";
 
 export const InProgressDropdown = () => {
-  const noop = () => {
-    // Do nothing
-  };
-
   return (
     <Dropdown
       value="Thinking..."
       options={[]}
       disabled={true}
       disabledPlaceholder="Thinking..."
-      onChange={noop}
     />
   );
 };