Duplicated workspaces share instances of Data providers

Description of problem:
When you duplicate some workspace, the data provider instances are shared between both original and duplicated workspace.

Version-Release number of selected component (if applicable):
Dashbuilder DR5 deployed on EAP 6.1

How reproducible:
always

Steps to Reproduce:
1. Login with root and navigate to workspace Showcase, page Data providers
2. Click "Delete data provider" for provider "Expense reports demo" -> alert "Cannot delete the data provider because it is being used by 5 KPI(s)" - accept alert
3. Click "Duplicate current workspace"
4. Repeat step 2 - only this time alert "Cannot delete the data provider because it is being used by 10 KPI(s)" is displayed. You will see the same alert when performing spet 2 in the duplicated workspace

Actual results:
The workspace duplication doesn't create unique DataProvider instances for the new workspace but instead reuses the instances used by the original workspace. This is also confirmed by inspecting the local application datasource.

Expected results:
I would expect the duplicated workspace to be completely independent of the original workspace (i.e. changes to one of them should not affect the other one) which is not the case if the Data Provider instances are shared.

One example where the problem manifests itself:
-User duplicates a workspace
-Now in the duplicated workspace he decides to delete data provider X
-He goes to management (via General configuration) and deletes all Y KPI panels dependent on provider X (because of referential integrity contraints)
-Then he goes to Data providers page and tries to delete the provider X
-He gets error, that the provider is used by Y KPI panels (that reference our provider X from the original workspace)
-If user only has access to duplicated workspace he will never be able to delete the provider Y until KPI's from original workspace are deleted