[AI Assistance] Show correct button when deleting

This will be further refactor to simplify the handling of the props
Waiting for the next milestone to reduce chances of regressions now.

Fixed: 378056161
Change-Id: I32c4b2cb3d4d13092b2d47f68c052fcf8aab7851
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6010832
Commit-Queue: Nikolay Vitkov <[email protected]>
Auto-Submit: Nikolay Vitkov <[email protected]>
Commit-Queue: Alex Rudenko <[email protected]>
Reviewed-by: Alex Rudenko <[email protected]>

Author: Lightning00Blade

front_end/panels/freestyler/FreestylerPanel.ts

@@ -703,6 +703,7 @@ export class FreestylerPanel extends UI.Panel.Panel {
     if (this.#currentAgent) {
       this.#agents.delete(this.#currentAgent);
       this.#currentAgent = undefined;
+      this.#cancel();
     }
 
     this.#viewProps.messages = [];