Json serilializer leaves out object of JsonObject type in additionalData

[andrueastman]

Related to microsoftgraph/msgraph-sdk-java#2063

The json serializer does not handle JsonObject types resulting in illegalState exception as only the property is written.

We should probably add a case for the same at

kiota-java/components/serialization/json/src/main/java/com/microsoft/kiota/serialization/JsonSerializationWriter.java

Line 471 in a853aae

if (valueClass.equals(String.class)) this.writeStringValue(key, (String) value);