This commit makes small improvements on the messaging menu with
the new module `mail_bot`:
[IMP] When OdooBot has a request, it now adds "+1" to the counter of
the messaging menu. The related preview also has a bold title,
and displays "(1)" next to the title.
[REF] Static previews are no longer in mail_service. This was only
used for "OdooBot has a request" preview. This logic has now
been moved to the module `mail_bot` (was previously in `mail`).
[FIX] Title of response of push notifications permission clearly
states whether permission has been granted or denied
(was displaying "[Object object]" before this commit).
Task-ID 1877502
Alexandre Kühn
f80bbb4b2a