[AI Assistance] Show checkbox for selected history entry

Bug: 383436398
Change-Id: I1412dff52cb37ee9b7e09dcfecd0bd88d37e92cf
Fixed: 383436398
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6088296
Commit-Queue: Ergün Erdoğmuş <[email protected]>
Auto-Submit: Samiya Caur <[email protected]>
Reviewed-by: Ergün Erdoğmuş <[email protected]>

Author: Samiya Caur

front_end/panels/ai_assistance/AiAssistancePanel.ts

@@ -669,9 +669,9 @@ export class AiAssistancePanel extends UI.Panel.Panel {
         continue;
       }
 
-      contextMenu.defaultSection().appendItem(title, () => {
+      contextMenu.defaultSection().appendCheckboxItem(title, () => {
         void this.#switchAgent(agent);
-      });
+      }, {checked: (this.#currentAgent === agent)});
     }
 
     const historyEmpty = contextMenu.defaultSection().items.length === 0;