Kotlin annotated services don't support value classes with suspended methods

[jrhee17]

Note that it seems like this issue is fixed in the newer versions of kotlin (1.9.20), but we should check this works once we upgrade.

kotlin side: https://youtrack.jetbrains.com/issue/KT-58887/Reflection-IllegalArgumentException-argument-type-mismatch-when-using-reflection-to-invoke-a-value-class-returning-function-that
spring side: spring-projects/spring-framework#27345
discord ref: https://discord.com/channels/1087271586832318494/1172096171318181918/1172417425933860904

Reproducer:

@Test
    fun fooTest() {
        runTest {
            val res = server.blockingWebClient({cb ->
                cb.addHeader(HttpHeaderNames.CONTENT_TYPE, "application/json")
                    .responseTimeoutMillis(0)
                    .writeTimeoutMillis(0)
            })
                .post("/hello/foo", """
                    {
                        "hello": "world!",
                        "hi": 123
                    }
                """.trimIndent())
            logger.info("res: ${res}")
        }
    }

    companion object {
        private val logger = LoggerFactory.getLogger(MyTest::class.java)

        @RegisterExtension
        val server: ServerExtension = object : ServerExtension() {
            override fun configure(sb: ServerBuilder) {
                sb.idleTimeoutMillis(0)
                    .requestTimeoutMillis(0)
                sb.annotatedService()
                    .pathPrefix("/hello")
                    .build(MyAnnotatedService())
                sb.errorHandler(object: ServerErrorHandler {
                    override fun onServiceException(
                        ctx: ServiceRequestContext,
                        cause: Throwable
                    ): HttpResponse? {
                        logger.warn("onServiceException: ", cause)
                        return null
                    }
                })
            }
        }

        data class Inner(val hello: String, val hi: Int)

        @JvmInline
        value class TestClass(val inner: Inner)

        private class MyAnnotatedService {
            @Post("/foo")
            @ProducesJson
            suspend fun foo(testClass: TestClass): TestClass {
                println("testClass :${testClass}")
                return TestClass(Inner("world", 456))
            }
        }
    }