[FIX] mail: click on link in a message preview while replying

When clicking on a mention (or a link) within the preview of the
message we're replying to, there was a traceback because we tried
to update a component which has already been deleted.

closes odoo/odoo#83912

Task-id: 2747321
Signed-off-by: Sébastien Theys (seb) <seb@odoo.com>

addons/mail/static/src/components/message_list/message_list.js

@@ -337,6 +337,9 @@ export class MessageList extends Component {
      * @param {ScrollEvent} ev
      */
     _onScrollThrottled(ev) {
+        if (!this.messageListView) {
+            return;
+        }
         const {
             orderedMessages,
             thread,

addons/mail/static/src/models/message_view/message_view.js

@@ -17,6 +17,9 @@ registerModel({
             this.update({
                 isHighlighted: true,
                 highlightTimeout: this.env.browser.setTimeout(() => {
+                    if (!this.exists()) {
+                        return;
+                    }
                     this.update({ isHighlighted: false });
                 }, 2000),
             });