Add the group assigned on ticket creation to history

[ArthurMinfotel]

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• I have performed a self-review of my code.

Description

Use hook item_add to create first record in glpi_plugin_escalade_histories when a group is assigned at creation.
Related to issues 261.

[stonebuzz]

Hi @ArthurMinfotel

can you resolve conflicts?

[stonebuzz]

And add unit tests ?

[ArthurMinfotel]

And add unit tests ?

I've added a test which check :

1. Was the history properly created if the ticket is created with a group assigned.
2. Was the first group assigned removed if the ticket is updated with 2 groups assigned (the one assigned in 1 and a new one).
3. Was the change of group assigned which happenned during 2 properly recorded in the history.

[stonebuzz]

Hi Arthur, I have my doubts about this PR's commits

this one :

Is already in core