In this commit we introduce a new module ``test_mail_sms`` that holds the
tests for sms application, like ``test_mail`` does for mail. Currently all
sms tests are inside ``test_mail_full``. After this commit code is moved
from ``test_mail_full`` into that module. Full testing module should be used
mainly to test integrations with a lot of submodules and for performance
tests, not testing details of SMS implementation.
We also add ``mass_mailing_sms`` as dependency of ``test_mass_mailing`` so
that both mailing types are tested in the same module. It eases maintenance
and writing of tests. Mass mailing SMS tests from `test_mail_full`` are
therefore moved in ``test_mass_mailing``.
This commit also allows some cleaning in classes used in tests, to have
classes in ``test_mail_sms`` and ``test_mail_full`` that contain everything
necessary to test mail features.
Task-2890111 (Test Mail/Mass Mailing: SMS tests reorganization and move)
Part-of: odoo/odoo#96223