[FIX] *: add missing model description

Some models did not specified a _description

addons/test_mail/models/test_mail_models.py

@@ -145,6 +145,7 @@ class MailModel(models.Model):
 
 class MailCC(models.Model):
     _name = 'mail.test.cc'
+    _description = "Test Email CC Thread"
     _inherit = ['mail.thread.cc']
 
     name = fields.Char()

addons/website_sale/wizard/payment_acquirer_onboarding_wizard.py

@@ -7,6 +7,7 @@ from odoo import models
 class PaymentWizard(models.TransientModel):
     _inherit = 'payment.acquirer.onboarding.wizard'
     _name = 'website.sale.payment.acquirer.onboarding.wizard'
+    _description = 'Website Payment acquire onboarding wizard'
 
     def _set_payment_acquirer_onboarding_step_done(self):
         """ Override. """

odoo/addons/test_new_api/models.py

@@ -250,6 +250,7 @@ class MultiLine(models.Model):
 class MultiLine2(models.Model):
     _name = 'test_new_api.multi.line2'
     _inherit = 'test_new_api.multi.line'
+    _description = 'Test New API Multi Line 2'
 
 
 class MultiTag(models.Model):