test: Add test coverage for JsonSchemaConverter property handling

[alxkm]

Description

This PR adds additional test coverage for the JsonSchemaConverter class to ensure proper handling of various JSON Schema properties during conversion to OpenAPI format.

Changes

• Added 3 new test cases to JsonSchemaConverterTests covering critical property conversion scenarios
• Tests ensure proper conversion of boolean values, enums, and OpenAPI-specific properties

Test Coverage

The new tests cover:

• Boolean additionalProperties handling (testing with true value)
• Enum property preservation with string array values
• OpenAPI-specific properties:
  • nullable boolean property
  • readOnly boolean property
  • writeOnly boolean property
  • Complex description object structure

Testing

All tests pass successfully and verify that the JsonSchemaConverter correctly:

• Preserves boolean property values
• Maintains enum arrays during conversion
• Properly handles OpenAPI-specific properties that may not exist in standard JSON Schema

[ilayaperumalg]

@alxkm Thanks for the PR improving the test coverage.

[ilayaperumalg]

Rebased and merged as 6593762