Workaround references list not updating (microsoft#232176)

Not the ideal fix but this makes it so that `ChatCollapsibleListContentPart` does not have a live version of the references list passed to it. The current code results in the item never being re-rendered because `hasSameContent` would always return true, so the references list would not update

There are a bunch of layers above this that all say they are readonly arrays too. Being readonly is correct from the consumer side, but it looks like the array does get mutated behind the scenes which is often unexpected

Author: mjbvz

src/vs/workbench/contrib/chat/common/chatModel.ts

@@ -492,7 +492,7 @@ export class ChatResponseModel extends Disposable implements IChatResponseModel
 
 	private readonly _contentReferences: IChatContentReference[] = [];
 	public get contentReferences(): ReadonlyArray<IChatContentReference> {
-		return this._contentReferences;
+		return Array.from(this._contentReferences);
 	}
 
 	private readonly _codeCitations: IChatCodeCitation[] = [];