[REF] mail: move composer 'force_send' field to computed

RATIONALE

Remove _onchange_template_id / defaults usage for composer fields. It
lacks control and make value computation hard to understand and predict.

PURPOSE

Split _onchange_template_id + default_get + get_record_data usage into editable
computed stored fields. Each field should have its own method with its triggers
(template, composition mode, ...).

SPECIFICATIONS

Improve composer to correctly compute field ``force_send`` in compute method.
It is currently computed in a default_get override.

It is set to True in mass mailing mode (send directly by default) and in
monorecord comment mode (send notifications right now). Batch comment delays
notification to use the email queue.

Task-2088884 (Mail: Use editable computed stored fields in composer)

Part-of: odoo/odoo#107356

addons/mail/wizard/mail_compose_message.py

@@ -69,14 +69,6 @@ class MailComposer(models.TransientModel):
         if 'create_uid' in fields_list and 'create_uid' not in result:
             result['create_uid'] = self.env.uid
 
-        # batch post mode by default use queues for notifications
-        if 'force_send' in fields_list and 'force_send' not in result:
-            result['force_send'] = (
-                result.get('composition_mode') != 'comment' or
-                (not result.get('res_domain') and
-                len(self._parse_res_ids(result.get('res_ids') or [])) <= 1)
-            )
-
         return {
             fname: result[fname]
             for fname in result if fname in fields_list
@@ -168,7 +160,8 @@ class MailComposer(models.TransientModel):
         compute="_compute_auto_delete_keep_log", readonly=False, store=True,
         help='Keep a copy of the email content if emails are removed (mass mailing only)')
     force_send = fields.Boolean(
-        'Send mailing or notifications directly')
+        'Send mailing or notifications directly',
+        compute='_compute_force_send', readonly=False, store=True)
     mail_server_id = fields.Many2one(
         'ir.mail_server', string='Outgoing mail server',
         compute='_compute_mail_server_id', readonly=False, store=True)
@@ -486,6 +479,15 @@ class MailComposer(models.TransientModel):
         toreset.auto_delete_keep_log = False
         (self - toreset).auto_delete_keep_log = True
 
+    @api.depends('composition_mode', 'model', 'res_domain', 'res_ids')
+    def _compute_force_send(self):
+        """ It is set to True in mass mailing mode (send directly by default)
+        and in monorecord comment mode (send notifications right now). Batch
+        comment delays notification to use the email queue. """
+        for composer in self:
+            composer.force_send = (composer.composition_mode == 'mass_mail' or
+                                   not composer.composition_batch)
+
     @api.depends('template_id')
     def _compute_mail_server_id(self):
         """ Copy value from template when updating it, if set on template. When