[14.0][FIX] attachment_zipped_download: Fix tests (remove addClassCleanup)

[victoralmau]

Fix tests (remove addClassCleanup)

Remove addClassCleanup to prevent error:

Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/odoo_test_helper/fake_model_loader.py", line 202, in restore_registry
    self.env.registry.setup_models(self.env.cr)
  File "/opt/odoo/custom/src/odoo/odoo/modules/registry.py", line 273, in setup_models
    model._setup_base()
  File "/opt/odoo/custom/src/odoo/odoo/models.py", line 2802, in _setup_base
    delattr(cls, name)
AttributeError: id

Please @pedrobaeza can you review it?

@Tecnativa

[pedrobaeza]

So this affects all the versions?

[victoralmau]

So this affects all the versions?

I have reviewed 15, 16, 17, and 18, and there are currently no similar errors in the tests for this module.

[victoralmau]

Related to OCA/odoo-test-helper#42

[victoralmau]

Similar error in other tests of 14 that use odoo_test_helper.

Related to OCA/odoo-test-helper#42