init interaction regardless of new icon or not
init interaction regardless of new icon or not

[issue #3976]

previously interaction only get inited when not reusing icon, i.e. when addIcon
flag is set to true. by taking the statement out of the if condition,
interaction is inited whenever setIcon is called.

stefanocudini/Leaflet,stefanocudini/Leaflet,tsantacruz/RotationalMarker,brah/Leaflet,codeator/Leaflet,nathancahill/Leaflet,RyanHickman/Leaflet,iOffice/Leaflet,iZucken/Leaflet,frogcat/Leaflet,rlugojr/Leaflet,akrzyzanowskino/TeamSE,scaddenp/Leaflet,jblarsen/Leaflet,frogcat/Leaflet,fab1an/Leaflet,Trufi/Leaflet,geoloep/Leaflet,Neorth/Leaflet,jasonoverland/Leaflet,fab1an/Leaflet,CapeSepias/Leaflet,nathancahill/Leaflet,tsantacruz/RotationalMarker,RyanHickman/Leaflet,jblarsen/Leaflet,iZucken/Leaflet,Neorth/Leaflet,iZucken/Leaflet,w8r/Leaflet,jasonoverland/Leaflet,brah/Leaflet,codeator/Leaflet,Neorth/Leaflet,AP-whitehat/Leaflet,iOffice/Leaflet,w8r/Leaflet,fab1an/Leaflet,AP-whitehat/Leaflet,davojta/Leaflet,hyperknot/Leaflet,hyperknot/Leaflet,akrzyzanowskino/TeamSE,msiadak/Leaflet,scaddenp/Leaflet,frogcat/Leaflet,CapeSepias/Leaflet,codeator/Leaflet,hyperknot/Leaflet,Trufi/Leaflet,stefanocudini/Leaflet,Leaflet/Leaflet,brah/Leaflet,bbecquet/Leaflet,nathancahill/Leaflet,CapeSepias/Leaflet,Ubisense/Leaflet,Ubisense/Leaflet,RyanHickman/Leaflet,davojta/Leaflet,geoloep/Leaflet,rlugojr/Leaflet,davojta/Leaflet,jblarsen/Leaflet,Trufi/Leaflet,scaddenp/Leaflet,jasonoverland/Leaflet,Ubisense/Leaflet,msiadak/Leaflet,sisou/Leaflet,sisou/Leaflet,msiadak/Leaflet,w8r/Leaflet,bbecquet/Leaflet,Leaflet/Leaflet,AP-whitehat/Leaflet,bbecquet/Leaflet,Leaflet/Leaflet,iOffice/Leaflet,tsantacruz/RotationalMarker,sisou/Leaflet,geoloep/Leaflet,rlugojr/Leaflet,akrzyzanowskino/TeamSE