*: calendar, note, test_mail.
This PR prepares the ground for the one introducing the new environment in the discuss app.
Indeed, the start helper won't be able to handle widget anymore. To solve this issues,
we're now adding the activityMenu widget to the systrayMenu.Items array, this will be
mapped by the createWebClient helper to component and added to the new systray item
registry.
task-2582313
closesodoo/odoo#91953
Related: odoo/enterprise#27614
Signed-off-by: Sébastien Theys (seb) <seb@odoo.com>