Edit transition must disable changing to-state

Problem/Motivation

When editing an executed transition, the to-state must not be changed

Steps to reproduce

- go to an entity with workflow field
- go to 'history' tab
- edit a transition ffom the list (make sure permission are set)
- Ther should be no options list for the to-state

Proposed resolution

Replace with formatter, just as in v1.7

Remaining tasks

User interface changes

API changes

Data model changes