[FIX] calendar: browse record using IrRules

Create a calendar meeting using Mark Demo. In the options of the event,
set the meeting as "Show Time as" = "Free". Using the admin user, send a
digest (KPI Digest module, technical > emails > digest email > send
now). It raises an User Error because the template cannot be rendered.

The problem is due to the way the "Show Time as" is implemented, the
"Free" option is used to not show the meeting in the different calendar
views. The events are hidden thanks to a record rule "Hide Private
Meetings".

Each digest is sent using the context of each subscripted user and not
the SuperUser ID 1. The call to `search_count` on `mail.message` calls
the dedicated `_search` of `mail.message` and ultimately end up in the
overriden `_find_allowed_model_wise` method of message in calendar.

That method does a browse of all the record ids containing new
messages in their chatter, but fail with an access error due to the
above record rule. Because it fails, the `kpi_mail_message_total_value`
compute fails and the field is missing when rendering the template.

Using `search` instead of `browse` ensures records unavailable due to a
record rule are filtered out.

opw-1966664

closes odoo/odoo#32735

Signed-off-by: Simon Goffin (sig) <sig@openerp.com>

addons/calendar/models/mail_message.py

@@ -28,6 +28,7 @@ class Message(models.Model):
     def _find_allowed_model_wise(self, doc_model, doc_dict):
         if doc_model == 'calendar.event':
             order = self._context.get('order', self.env[doc_model]._order)
-            for virtual_id in self.env[doc_model].browse(doc_dict).get_recurrent_ids([], order=order):
+            records = self.env[doc_model].search([('id', 'in', list(doc_dict))])
+            for virtual_id in records.get_recurrent_ids([], order=order):
                 doc_dict.setdefault(virtual_id, doc_dict[get_real_ids(virtual_id)])
         return super(Message, self)._find_allowed_model_wise(doc_model, doc_dict)