fix: nest generic test arguments under arguments in integration tests

[shauneccles]

Summary

• The shipped models/ YAML files were already fixed in 78d73ea, but the integration test YAML files were missed
• Nests generic test parameters under arguments: in core.yml and graph.yml to resolve MissingArgumentsPropertyInGenericTestDeprecation on dbt-core >= 1.11
• Fixes 4 instances: dbt_utils.expression_is_true, dbt_utils.unique_combination_of_columns, and accepted_values (×2)

Closes #569

Test plan

• CI passes on dbt-core >= 1.11 without MissingArgumentsPropertyInGenericTestDeprecation warnings
• Integration tests still pass with the updated YAML structure

🤖 Generated with Claude Code

[b-per]

Thanks! I will have a look. I am just wondering how we got the integration tests to pass on Fusion without this being implemented 🤔

[b-per]

I dug further. The reason that Fusion was not raising issues in the past was because those tests were entirely skipped.

The package adds models from the upstream package in its own YAML which is supported in dbt Core but not in Fusion. We need to revisit the whole testing approach to avoid this discrepancy.

I will close this PR to work on an alternative approach and keep the issue opened.