[GSS](6.4.z) Only 15 workitemhandlers can be added to kie-deployment-descriptor.xml via business central console

Description of problem:
The Deployment Descriptors page can only display 15 workItemHandlers,we can not add any more handlers via the business-central console, and if we add more directly to the kie-deployment-descriptor.xml file, then they will not be displayed in Business Central console.

Steps to Reproduce:
1. Try to add more than 15 WorkItemHandlers through UI

Actual results:
Deployment Descriptors page can only add/display 15 WorkItemHandlers.

Expected results:
we should be able to add more than 15 WorkItemHandlers through console.

Additional info:
We can see same behaviour with Task/EventListener