[JENKINS-64483] Hide collapse link if it isn't possible
[JENKINS-64483] Hide collapse link if it isn't possible

Also document the optional 'collapseText'

viqueen/jenkins,MarkEWaite/jenkins,MarkEWaite/jenkins,rsandell/jenkins,ikedam/jenkins,rsandell/jenkins,rsandell/jenkins,pjanouse/jenkins,daniel-beck/jenkins,DanielWeber/jenkins,daniel-beck/jenkins,damianszczepanik/jenkins,pjanouse/jenkins,rsandell/jenkins,pjanouse/jenkins,daniel-beck/jenkins,pjanouse/jenkins,MarkEWaite/jenkins,DanielWeber/jenkins,jenkinsci/jenkins,MarkEWaite/jenkins,jenkinsci/jenkins,MarkEWaite/jenkins,jenkinsci/jenkins,pjanouse/jenkins,viqueen/jenkins,v1v/jenkins,ikedam/jenkins,daniel-beck/jenkins,ikedam/jenkins,ikedam/jenkins,ikedam/jenkins,v1v/jenkins,v1v/jenkins,jenkinsci/jenkins,jenkinsci/jenkins,v1v/jenkins,v1v/jenkins,MarkEWaite/jenkins,jenkinsci/jenkins,ikedam/jenkins,DanielWeber/jenkins,jenkinsci/jenkins,MarkEWaite/jenkins,DanielWeber/jenkins,daniel-beck/jenkins,damianszczepanik/jenkins,MarkEWaite/jenkins,pjanouse/jenkins,viqueen/jenkins,viqueen/jenkins,ikedam/jenkins,pjanouse/jenkins,damianszczepanik/jenkins,damianszczepanik/jenkins,DanielWeber/jenkins,viqueen/jenkins,daniel-beck/jenkins,viqueen/jenkins,damianszczepanik/jenkins,rsandell/jenkins,v1v/jenkins,DanielWeber/jenkins,ikedam/jenkins,jenkinsci/jenkins,daniel-beck/jenkins,rsandell/jenkins,rsandell/jenkins,damianszczepanik/jenkins,damianszczepanik/jenkins,v1v/jenkins,rsandell/jenkins,damianszczepanik/jenkins,viqueen/jenkins,daniel-beck/jenkins,DanielWeber/jenkins