Add test_configuration to SameSimTestSuite to fix --export-json (fixes #1138)

[mustafacicek-eee]

Description

Fixes #1138.

When exporting tests to JSON using --export-json, _main_export_json() iterates over all test suites and accesses test_suite.test_configuration to retrieve the test configuration mapping for each test case:

test_information = test_suite.test_information
test_configuration = test_suite.test_configuration
for name in test_suite.test_names:
    info = test_information[name]
    config = test_configuration[name]

When testbenches specify -- vunit: run_all_in_same_sim, tests are grouped into a SameSimTestSuite rather than TestSuiteWrapper. SameSimTestSuite defines test_names and test_information, but was missing the test_configuration property, resulting in:

AttributeError: 'SameSimTestSuite' object has no attribute 'test_configuration'

Solution

1. Added test_configuration property to SameSimTestSuite in vunit/test/suites.py, returning a dictionary mapping each full test name to self._configuration (mirroring test_information).
2. Added unit test test_export_json_same_sim in tests/unit/test_ui.py to test --export-json on testbenches with same_sim=True.
3. Added news fragment docs/news.d/1138.bugfix.rst.

Verification

Ran the unit test suite:

• test_export_json passed.
• test_export_json_same_sim passed.