[➕ Feature]: Jira On-Prem provider cannot transition a ticket

Is your feature request related to a problem? Please describe.

The Jira Cloud provider takes transition_to in _notify (keep/providers/jira_provider/jira_provider.py:557), matches the name against the transitions Jira offers for that ticket and applies it, both to an existing ticket and to one it has just created (__get_available_transitions and __transition_issue, lines 277 and 307).

The on-prem provider's _notify (keep/providers/jiraonprem_provider/jiraonprem_provider.py:513) has no such parameter. A workflow that closes a ticket when its alert resolves runs on Cloud and cannot be moved to Server or Data Center by changing type, even though the API behind it is the same: /rest/api/2/issue/{key}/transitions, GET for the list and POST to apply one.

Describe the solution you'd like

transition_to on the on-prem provider, spelled the same way as on Cloud: the name matched case-insensitively, applied after an update and after a create, and an unknown name failing with the list of the transitions that do exist.

Describe alternatives you've considered

Calling the transitions endpoint from a generic HTTP step. That means configuring the personal access token a second time outside the Jira provider and looking the transition id up by hand for every project.

Additional context

A PR implementing this follows.