[Application Runner] Passing empty objects instead of null

[Katerina-Charakhovich]

Name and Version

Admin: [BE]0.14.0-rc

What steps will reproduce the bug?

1. Configure Application Runner with applicationTypeSchemaEndpoint.
2. Do not provide values for inline schema fields ($defs, properties, etc.).
3. During mapping, empty maps ({}) are created instead of keeping these fields null.
4. Core receives and persists these empty objects.

What is the expected behavior?

If inline schema fields are not provided, they should remain null and must not be converted into empty maps.

What do you see instead?

When values are absent, empty maps ({}) are created for $defs, properties

Additional information

No response