Fix/transfer log followup

[giovanny07]

Summary

• Wrong item type for transfer log: The transfer was logged as a TicketTask,
  which represents work to be done. ITILFollowup is the correct type to record
  an event that has already occurred (the transfer itself).
• Unified content: Entity name, group name (when selected), and justification
  (when provided) are now built into a single followup entry instead of relying
  on fragmented string concatenation. Each section is guarded with !empty() so
  it only appears when actually set.

Changes

src/Ticket.php:

• Replaced use TicketTask / use Planning with use ITILFollowup.
• Replaced the TicketTask::add() call with ITILFollowup::add() using
  itemtype = Ticket::class and items_id.
• Refactored content building to append group and justification only when present.

Test plan

• Transfer a ticket with no group and no justification — one private followup is
  created with "Escalation to [entity]"
• Transfer with a group selected — followup includes "in the group [name]"
• Transfer with justification text — followup includes the justification after a
  line break
• Transfer with both group and justification — single followup contains all three
  parts in one entry
• Confirm no TicketTask entries are created by the plugin on transfer

[dhrzic]

On v10 when automatic task is added, notification is not being generated, can you also check this? Or maybe add a dedicated notification for this event?

[giovanny07]

The original TicketTask relied on the add_task notification event, which is not enabled by default in most GLPI setups. ITILFollowup uses the add_followup event, which is enabled by default. With is_private = true, the notification is sent only to tech-side actors — the requester is still informed of the transfer via the update_ticket event that fires when the entity changes.
A dedicated plugin notification event (e.g. ticket_transferred) would allow finer control over recipients and could be added as a separate enhancement.

[tsmr]

Please add an option into plugin setup for choose to create a followup or a task