[FIX] mail: remove unexisting field from template

https://github.com/odoo/odoo/pull/98262 introduce a t-out on a field that
doesn't exist.

closes odoo/odoo#99381

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

addons/mail/static/src/components/notification_message_view/notification_message_view.xml

@@ -3,7 +3,7 @@
     <t t-name="mail.NotificationMessageView" owl="1">
         <div class="o_NotificationMessageView d-flex justify-content-center">
             <div class="flex-grow-1"/>
-            <div class="text-500 small px-3" t-out="notificationMessageView.notificationText">
+            <div class="text-500 small px-3">
                 <span class="d-inline" t-esc="notificationMessageView.message.authorName"/> <t t-out="notificationMessageView.message.prettyBodyAsMarkup"/>
             </div>
             <div class="flex-grow-1"/>