Fix invalid validation error after workflow duplication

1. Create a new workflow wf1
2. In the Graph view for wf1, add an "Approve" task node between the default "Start" and "End" nodes and save.
3. Duplicate wf1 and name the clone wf2.
4. Open the Graph view for wf2 and navigate to any other view ("Process Definitions", for example).
5. The dirty checking will trigger, prompting the user to save changes.
6. Click save and validation errors will show for wf2:

Transition 'approve' on node 'Approve' is not used in the graph.

Expected:
no validation error should be shown when graph configuration is correct.

Notes:
Problem is that generated name for the transition is incorrect during copy:

example origin transition

<transition>
        <condition><![CDATA[NodeVariables["button"] =="approve"]]></condition>
        <targetId><![CDATA[stop-node]]></targetId>
        <name><![CDATA[approveTask10de]]></name>
        <label><![CDATA[approve]]></label>
</transition>

after copy

<transition>
        <condition><![CDATA[NodeVariables["button"] =="approve"]]></condition>
        <name><![CDATA[approveundefined]]></name>
        <label><![CDATA[approve]]></label>
</transition>

=> notice that transition name is now approveundefined instead of approve[new task id]