Cannot serialize option of anyval in a collection

I have a sample test here:

```
"Anyvals" should "serialize json" in {
val groups = (0 until 10).map(_ =>
AnyHolder(
Some(TestAny("data"))
))

val objectMapper = new ObjectMapper().registerModule(DefaultScalaModule)
println(objectMapper.writeValueAsString(data))
}
}

case class AnyHolder(
testAny: Option[TestAny]
)

case class TestAny(data: String) extends AnyVal
```

This fails with

```
tests.TestAny cannot be cast to java.lang.String (through reference chain: scala.collection.convert.IterableWrapper[0]->tests.AnyHolder["testAny"])
com.fasterxml.jackson.databind.JsonMappingException: tests.TestAny cannot be cast to java.lang.String (through reference chain: scala.collection.convert.IterableWrapper[0]->tests.AnyHolder["testAny"])
at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:378)
at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:338)
at com.fasterxml.jackson.databind.ser.std.StdSerializer.wrapAndThrow(StdSerializer.java:342)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:686)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:157)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:149)
at com.fasterxml.jackson.module.scala.ser.IterableSerializer$class.serializeContents(IterableSerializerModule.scala:28)
at com.fasterxml.jackson.module.scala.ser.UnresolvedIterableSerializer.serializeContents(IterableSerializerModule.scala:56)
```

Using jackson-core 2.7.4, jackson-databind 2.7.4, jackson-scala-module 2.7.4

Are there any workarounds to get this to work?