[FIX] mail: raise a missing email error instead of crash when logging without email

Currently when posting a message if the author has no email address an user
error is raised. Indeed as posting a message goes through the process of
creating notifications and sending emails an email address is required on
the user.

In saas 11.2 a _message_log shortcut has been added to log notes and in saas
11.3 a message_notify has been added to notify peopel of a custom content.
Those methods should have the same behavior when author has no email.
Currently there is a crash when trying to encode its email. After this commit
an exceptions is raised like classic post.

This commit is a manual forward-port of 3a978cc64e6b1d8aca7cfd5d4e319bcb302dd262 as well as an improvement
to fix the newly-introduced message_notify method.

addons/mail/models/mail_message.py

@@ -28,7 +28,7 @@ class Message(models.Model):
     def _get_default_from(self):
         if self.env.user.email:
             return formataddr((self.env.user.name, self.env.user.email))
-        raise UserError(_("Unable to send email, please configure the sender's email address."))
+        raise UserError(_("Unable to post message, please configure the sender's email address."))
 
     @api.model
     def _get_default_author(self):

addons/mail/models/mail_thread.py

@@ -1973,16 +1973,16 @@ class MailThread(models.AbstractModel):
         kw_author = kwargs.pop('author_id', False)
         if kw_author:
             author = self.env['res.partner'].sudo().browse(kw_author)
-            email_from = formataddr((author.name, author.email))
         else:
             author = self.env.user.partner_id
-            email_from = formataddr((author.name, author.email))
+        if not author.email:
+            raise exceptions.UserError(_("Unable to notify message, please configure the sender's email address."))
 
         msg_values = {
             'subject': subject,
             'body': body,
             'author_id': author.id,
-            'email_from': email_from,
+            'email_from': formataddr((author.name, author.email)),
             'message_type': 'notification',
             'partner_ids': partner_ids,
             'model': False,
@@ -2007,16 +2007,16 @@ class MailThread(models.AbstractModel):
         kw_author = kwargs.pop('author_id', False)
         if kw_author:
             author = self.env['res.partner'].sudo().browse(kw_author)
-            email_from = formataddr((author.name, author.email))
         else:
             author = self.env.user.partner_id
-            email_from = formataddr((author.name, author.email))
+        if not author.email:
+            raise exceptions.UserError(_("Unable to log message, please configure the sender's email address."))
 
         message_values = {
             'subject': subject,
             'body': body,
             'author_id': author.id,
-            'email_from': email_from,
+            'email_from': formataddr((author.name, author.email)),
             'message_type': message_type,
             'model': kwargs.get('model', self._name),
             'res_id': self.ids[0] if self.ids else False,