feat: auto populate propertyOrdering in Schema builder and transformers

[hemasekhar-p]

Fixes #1169

Description

Automatically populates propertyOrdering with property keys when constructing a Schema object with multiple properties if propertyOrdering was not explicitly set.

Changes

• Updated Schema.Builder.build() to auto-populate propertyOrdering if omitted and properties has > 1 key.
• Updated Transformers.tSchema helper to recursively populate propertyOrdering on nested object schemas and items.
• Added unit test coverage in TransformersTest.java.

Test Coverage

• Explicit user property ordering is preserved.
• Single-property and empty schemas remain untouched.