test: add ModuleBase mocking for appstreams unit tests

Mock dnf.module.module_base to support testing the ModuleBase API
refactoring. Without this mock, the import sets dnf.module=None and
tests fail when trying to access module_base.ModuleBase().

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: nickanderson

promise-types/appstreams/test_appstreams_logic.py

@@ -13,8 +13,12 @@
 # Mock dnf module before importing the promise module
 mock_dnf = MagicMock()
 mock_dnf.exceptions = MagicMock()
+mock_dnf.module = MagicMock()
+mock_dnf.module.module_base = MagicMock()
 sys.modules["dnf"] = mock_dnf
 sys.modules["dnf.exceptions"] = mock_dnf.exceptions
+sys.modules["dnf.module"] = mock_dnf.module
+sys.modules["dnf.module.module_base"] = mock_dnf.module.module_base
 
 import appstreams as appstreams_module  # noqa: E402