crm,credential: repair Ticket_getWorkflowStateTranslatedTitle for ERP5 workflow

`state_var` is now a compatibility alias calling getStateVariable, which
has a default value of `simulation_state`. As a result, this script was
attempting to call getSimulationStateTranslatedTitle on credential
requests, because they have an interaction workflow in their chain.

This fixes by implementing the full logic using new ERP5 workflow API.