test: add tests for 90%+ coverage on spp_case_base

- Enable test_compliance_generated (1190 lines at 0% coverage) by adding
  import to tests/__init__.py
- Fix 21 wrong menu visibility assertions for unrestricted menus (no
  groups= attribute) from assertFalse to assertTrue
- Fix _menu_visible helper to check group_ids with has_group() for
  proper implied group resolution instead of unreliable search([])
- Add test_case_models.py with 41 tests covering case_assessment,
  case_referral, case_note, and case_visit model methods

Author: gonzalesedwin1123

spp_case_base/tests/__init__.py

@@ -4,3 +4,5 @@
 from . import test_case_intervention_plan
 from . import test_case_intervention
 from . import test_case_security
+from . import test_compliance_generated
+from . import test_case_models