test(oas3): add regression tests for oneOf/anyOf parameter explode behavior

[maruthang]

Description

Added regression tests verifying that query parameters with oneOf/anyOf schemas correctly generate object default values when using style:form/explode:true. The underlying bug was already fixed by the composeJsonSchema method in parameter-row.jsx and the swagger-client 3.37.1 upgrade. These tests prevent future regressions.

Motivation and Context

Closes #10002

Query parameters with oneOf schemas and style:form/explode:true were not being properly exploded — the parameter value was not generated correctly when the schema used composition keywords. The bug is now fixed in the current codebase; this PR adds test coverage to prevent future regressions.

How Has This Been Tested?

3 new unit tests in test/unit/bugs/10002-oneof-param-explode.jsx:

• oneOf object parameter generates correct default value
• anyOf object parameter generates correct default value
• oneOf parameter with resolved $ref ($$ref marker) generates correct default value

All tests pass locally with npm run test:unit.

Screenshots (if appropriate)

N/A — test-only change, no UI modifications.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist

• My change requires no change to documentation
• I have added tests to cover my changes
• All new and existing tests pass
• I have updated the documentation accordingly (N/A)