Kotlin: address KT-86046

Kotlin 2.4.20-RC marks public K1 APIs with K1Deprecation under KT-86046 and rejects the previous repeatable-annotation IR access path.

Opt in to K1Deprecation for 2.4.20 and later, and use the existing annotationClass compatibility extension.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>