[kotlin][client] Fix Parcelable oneOf/anyOf sealed interfaces with kotlinx_serialization

[4brunu]

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Summary by cubic

Fixes Parcelable generation for Kotlin oneOf/anyOf sealed interfaces with kotlinx_serialization. Unions now implement Parcelable, and wrapper value classes are @Parcelize, resolving Android parcelization and compile issues.

• Bug Fixes
  • For parcelizeModels with kotlinx_serialization, generate sealed interface … : Parcelable for oneOf/anyOf unions.
  • Add @Parcelize to each inline wrapper value class inside the union.
  • Skip top-level @Parcelize on the interface when using kotlinx_serialization to avoid conflicts.

^{Written for commit 036b653. Summary will update on new commits.}

[cubic-dev-ai]

All reported issues were addressed across 12 files

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