[ENH] Trackers : fix invalid arguments passed (implode)
When editing a tracker properties, on feature tab, if all attachement attributes (Sortable) are not checked, $input->orderAttachments is null. Related task (GlitchTip issue)
When editing a tracker properties, on feature tab, if all attachement attributes (Sortable) are not checked, $input->orderAttachments is null. Related task (GlitchTip issue)