Add vote step to REST API

Description

The current implementation of the REST API endpoints:

  • GET /webapi/v2/approvals

  • GET /webapi/v2/definitions

does not include proper support for steps of type VOTE.
We need to update the data models to include VOTE-type steps both when executing definition and approvals REST API.

This includes:

  • Ensuring VOTE steps are correctly represented in the response payloads

  • Including any additional fields specific to VOTE steps

  • Ensuring backward compatibility