Update GH workflow with new samples

Author: diastremskii

.github/workflows/samples-kotlin-client.yaml

@@ -72,6 +72,7 @@ jobs:
           - samples/client/others/kotlin-jvm-okhttp-path-comments
           - samples/client/others/kotlin-integer-enum
           - samples/client/petstore/kotlin-allOf-discriminator-kotlinx-serialization
+          - samples/client/others/kotlin-oneOf-discriminator-kotlinx-serialization
     steps:
       - uses: actions/checkout@v5
       - uses: actions/setup-java@v5