cubicweb #3013720 let on_fire_transition match a list of transitions [validation pending]

there's no reason to restrict it to a single trname, and sometimes can be useful to select on one of several transitions

prioritynormal
typeenhancement
done in3.18.0
load0.500
load left0.000
closed by#4da3ef764395 [predicates] allow multiple transition names in on_fire_transition (closes #3013720)
patch[predicates] allow multiple transition names in on_fire_transition (closes #3013720) [applied]