Simplify acquisition of unboxed type

Because the return value of creator handled by KotlinModule is always an unboxed type.

Author: k163377

src/main/kotlin/io/github/projectmapk/jackson/module/kogera/Converters.kt

@@ -29,7 +29,6 @@ internal class ValueClassUnboxConverter<T : Any>(val valueClass: Class<T>) : Std
     private val unboxMethod = valueClass.getDeclaredMethod("unbox-impl").apply {
         if (!this.isAccessible) this.isAccessible = true
     }
-    val unboxedClass: Class<*> = unboxMethod.returnType
 
     override fun convert(value: T): Any? = unboxMethod.invoke(value)
 

src/main/kotlin/io/github/projectmapk/jackson/module/kogera/deser/deserializers/KotlinDeserializers.kt

@@ -169,7 +169,7 @@ internal class KotlinDeserializers(
             rawClass == KotlinDuration::class.java ->
                 JavaToKotlinDurationConverter.takeIf { useJavaDurationConversion }?.delegatingDeserializer
             rawClass.isUnboxableValueClass() -> findValueCreator(type, rawClass, cache.getJmClass(rawClass)!!)?.let {
-                val unboxedClass = cache.getValueClassUnboxConverter(rawClass).unboxedClass
+                val unboxedClass = it.returnType
                 val converter = cache.getValueClassBoxConverter(unboxedClass, rawClass)
                 WrapsNullableValueClassBoxDeserializer(it, converter)
             }