title: Json to object deserialization issue in Graphql-spqr
body: <p>Json to GraphQLArgumetn object conversion failing in graphql-spqr.</p>
  
  <p>tried adding GraphQLInterface(with autodiscovery true and scanpackage) to above abstract classes
  and GraphQLtype type all concrete classes.</p>
  
  <p>My graph query:</p>
  
  <pre><code>query contactsQuery($searchQuery : QueryInput) { contacts(searchQuery:$searchQuery){id}}
  variables:{"searchQuery":{"bool":{"conditions":[{"must":{"matches":[{"singleFieldMatch":{"boost":null,"field":"firstname","value":"siddiq"}}],"bool":null}}]}})
  </code></pre>
  
  <p>Java code:</p>
  
  <pre class="lang-java prettyprint-override"><code>@JsonTypeInfo(use=JsonTypeInfo.Id.NAME,include=JsonTypeInfo.As.WRAPPER_OBJECT)
  @JsonSubTypes({@type(value = Must.class, name="must"),@type(value = MustNot.class, name="mustNot")})
  public abstract class Condition
  </code></pre>
  
  <pre class="lang-java prettyprint-override"><code>@JsonTypeInfo(use=JsonTypeInfo.Id.NAME,include=JsonTypeInfo.As.WRAPPER_OBJECT)
  @JsonSubTypes({@type(value = SingleFieldMatch.class, name="singleFieldMatch"),@type(value = MultiFieldMatch.class, name="multiFieldMatch")})
  public abstract class Match
  </code></pre>
  
  <pre class="lang-java prettyprint-override"><code>@GraphQLQuery(name = "contacts")
  public List getContacts(@GraphQLArgument(name ="searchQuery") Query query)
  </code></pre>
  
  <p>Still it's throwing error unknown field error etc. Not sure which configuration is missing.
  Building GraphQLSchema with AnnotatedResolvedBuilder, base package configured JacksonValueMappperFactory and singleton services.</p>