Improve DANGEROUS_disableRequiredPropertiesCheck so that it works with primitive types

[swallez]

This workaround doesn't work with primitive types, causing errors like: java.lang.NullPointerException: Cannot invoke "java.lang.Long.longValue()" because the return value of "co.elastic.clients.util.ApiTypeHelper.requireNonNull(Object, Object, String)" is null.

Primitive types should be set to their default values when the workaround is enabled.