Add tests for a particular use case of DH

[sergei-maertens]

Taiga DH 864

Changes

• Added test with configuration and wrong expectations (expected failure)
• Updated test with workaround to prevent the schema validation issue

I've also checked out the wrong expectation situation and reverted the #6007 fix locally, which produced a passing test:

diff --git a/src/openforms/registrations/contrib/objects_api/submission_registration.py b/src/openforms/registrations/contrib/objects_api/submission_registration.py
index d6129fd8e..9afc8d15c 100644
--- a/src/openforms/registrations/contrib/objects_api/submission_registration.py
+++ b/src/openforms/registrations/contrib/objects_api/submission_registration.py
@@ -474,7 +474,7 @@ class ObjectsAPIV2Handler(ObjectsAPIRegistrationHandler[RegistrationOptionsV2]):
 
         all_values = state.get_data(
             include_static_variables=True,
-            include_unsaved=True,
+            include_unsaved=False,
         )
         # update with the registration static values - a special subtype of static
         # variables. They're possibly derived from user input.

(open-forms) ➜  open-forms git:(06fd4fd92) ✗ runtests src -k test_conditional_fieldset_inside_repeating_group                                                                                                     
Found 1 test(s).
Using existing test database for alias 'default'...
System check identified no issues (0 silenced).
u
======================================================================
UNEXPECTED SUCCESS: test_conditional_fieldset_inside_repeating_group (openforms.registrations.contrib.objects_api.tests.test_backend_v2.ObjectsAPIBackendV2Tests.test_conditional_fieldset_inside_repeating_group)
----------------------------------------------------------------------
Ran 1 test in 0.659s

FAILED (unexpected successes=1)
Preserving test database for alias 'default'...

Checklist

Check off the items that are completed or not relevant.

• Impact on features

  • Checked copying a form
  • Checked import/export of a form
  • Config checks in the configuration overview admin page
  • Checked new model fields are usable in the admin
  • Problem detection in the admin email digest is handled

• Dockerfile/scripts

  • Updated the Dockerfile with the necessary scripts from the ./bin folder

• Commit hygiene

  • Commit messages refer to the relevant Github issue
  • Commit messages explain the "why" of change, not the how

• Documentation

  • Added documentation which describes the changes

[skip: e2e]

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.10%. Comparing base (66689e4) to head (3335a97).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6306   +/-   ##
=======================================
  Coverage   97.10%   97.10%           
=======================================
  Files         869      869           
  Lines       33147    33147           
  Branches     3048     3048           
=======================================
  Hits        32189    32189           
  Misses        646      646           
  Partials      312      312           

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[viktorvanwijk]

After reading up on the problem in Taiga: makes sense :)