fix: ensure guest-embedder map is updated when webview is removed (#23342)

There are use cases of webview where the container holding the webview is not
actually destroyed first, instead just webview gets removed from DOM, in such
situations the browser process map is not updated accordingly and holds reference
to stale guest contents, and any window operations like scroll, resize or keyboard
events that has to chain through browser embedder will lead to UAF crash.

Ref: https://github.com/microsoft/vscode/issues/92420

lib/renderer/web-view/web-view-element.ts

@@ -66,6 +66,9 @@ const defineWebViewElement = (v8Util: NodeJS.V8UtilBinding, webViewImpl: typeof
         return;
       }
       guestViewInternal.deregisterEvents(internal.viewInstanceId);
+      if (internal.guestInstanceId) {
+        guestViewInternal.detachGuest(internal.guestInstanceId);
+      }
       internal.elementAttached = false;
       this.internalInstanceId = 0;
       internal.reset();