[FIX] calendar: avoid recomputing fields at unlink

As unlinking calendar events leads to separate flows depending on the
event being recurrent some fields are recomputed in cache even if records
have already been deleted. This leads to issues when computing recurrence
and accessing some event data. Let us therefore avoid recomputing fields
when unlinking events.

addons/calendar/models/calendar.py

@@ -1524,7 +1524,7 @@ class Meeting(models.Model):
         partner_ids = events.mapped('partner_ids').ids
 
         records_to_exclude = self.env['calendar.event']
-        records_to_unlink = self.env['calendar.event']
+        records_to_unlink = self.env['calendar.event'].with_context(recompute=False)
 
         for meeting in self:
             if can_be_deleted and not is_calendar_id(meeting.id):  # if  ID REAL