Update Outbox code for Java SDK

[mcruzdev]

Describe the issue
Actually the code for use Outbox pattern uses a Java code not present in the Java SDK.

URL of the docs
https://docs.dapr.io/developing-applications/building-blocks/state-management/howto-outbox

Expected content

A code that reflects the current Java SDK.

Additional context

There is an example on Java SDK side: dapr/java-sdk#1582