[IMP] models: remove orphan translations

Same logic as for the mail.message or ir.attachment, when a record is deleted,
drop the ir.translations linked to it as well.

Fixes odoo/odoo#25105

Co-authored-by: Raphael Collet <rco@odoo.com>

closes odoo/odoo#30721

odoo/models.py

@@ -3114,6 +3114,7 @@ class BaseModel(MetaModel('DummyModel', (object,), {'_register': False})):
             Data = self.env['ir.model.data'].sudo().with_context({})
             Defaults = self.env['ir.default'].sudo()
             Attachment = self.env['ir.attachment']
+            Translation = self.env['ir.translation'].sudo()
 
             for sub_ids in cr.split_for_in_conditions(self.ids):
                 query = "DELETE FROM %s WHERE id IN %%s" % self._table
@@ -3144,6 +3145,15 @@ class BaseModel(MetaModel('DummyModel', (object,), {'_register': False})):
                 if attachments:
                     attachments.unlink()
 
+                if any(field.translate for field in self._fields.values()):
+                    # For the same reason, remove the relevant records in ir_translation
+                    translations = Translation.search([
+                        ('type', 'in', ['model', 'model_terms']),
+                        ('name', '=like', self._name+',%'),
+                        ('res_id', 'in', sub_ids)])
+                    if translations:
+                        translations.unlink()
+
             # invalidate the *whole* cache, since the orm does not handle all
             # changes made in the database, like cascading delete!
             self.invalidate_cache()