[FIX] mail: prevent a traceback when an onclick is triggered on an empty

m2o avater user widget

This commit's purpose is to prevent a traceback when the user click on
an empty avatar user icon.

task-3254564

closes odoo/odoo#117374

Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>

addons/mail/static/src/web/fields/many2one_avatar_user_field/many2one_avatar_user_field.js

@@ -21,7 +21,9 @@ const userChatter = {
     },
 
     onClickAvatar() {
-        this.openChat(this.props.record.data[this.props.name][0]);
+        const id = this.props.record.data[this.props.name][0] ?? false
+        if (id !== false)
+            this.openChat(id);
     },
 };