[ASYNCAPI] Custom validators bug

[marioTemprano]

In AsyncApi generator (we should check if in openApi generator its ok) the custom validators are bad placed and wrongly referenced.

In this image can be seen that the generated package name and the folder structure are different

This is how a custom validator is referenced and were its paced.

This is the async api file used for the screenshots.
event-api.yml.zip

[joseegman]

Hi! I've created PR #413 to fix this.

The bug: when a message payload is an inline object (a map of properties with $ref without type/properties, like the CreateOrderEvent payload in the attached spec), the generator crashed because a SchemaFieldObject ended up with a null baseName.

The fix detects inline object schemas in ApiTool.isInlineObject and processes them as regular properties in ModelBuilder.getFields. A regression test using the exact event-api.yml from this issue verifies that all generated files (DTOs, consumer/producer, and custom validators) declare a package that matches their folder structure.