[FIX] calendar, event: do not send emails to canceled attendees

Backport of https://github.com/odoo/odoo/commit/cf753a7fdf1739dcf37d2ad74f4c8efb3d4ff3b3
(it was finally considered as a real bug to fix in stable versions
from 10.0).

opw-769955
opw-814459
Closes https://github.com/odoo/odoo/pull/22882

addons/calendar/models/calendar.py

@@ -401,7 +401,7 @@ class AlarmManager(models.AbstractModel):
 
         result = False
         if alarm.type == 'email':
-            result = meeting.attendee_ids._send_mail_to_attendees('calendar.calendar_template_meeting_reminder', force_send=True)
+            result = meeting.attendee_ids.filtered(lambda r: r.state != 'declined')._send_mail_to_attendees('calendar.calendar_template_meeting_reminder', force_send=True)
         return result
 
     def do_notif_reminder(self, alert):

addons/event/models/event.py

@@ -272,7 +272,7 @@ class EventEvent(models.Model):
         return res
 
     @api.one
-    def mail_attendees(self, template_id, force_send=False, filter_func=lambda self: True):
+    def mail_attendees(self, template_id, force_send=False, filter_func=lambda self: self.state != 'cancel'):
         for attendee in self.registration_ids.filtered(filter_func):
             self.env['mail.template'].browse(template_id).send_mail(attendee.id, force_send=force_send)