[BUG] mapping is sometimes lost in schema generation

[lgmyrek]

Tapir version: 1.10.12

Scala version: 2.13.14

Describe the bug

Mapping for coproduct schemas is for some reason lost during the generation while oneOf contains proper ref
eg.

    Nodes_WrappedString:
      title: Nodes_WrappedString
      oneOf:
      - $ref: '#/components/schemas/Node_WrappedString'
      discriminator:
        propertyName: type
        mapping:
          Node: Defs.Node

How to reproduce?
https://scastie.scala-lang.org/anwau101QxK0XfOZ8TeK9w

Additional information
context:
https://softwaremill.community/t/custom-recursive-schemas/419/4