refactor(view-slot): re-use animatable element discovery logic
refactor(view-slot): re-use animatable element discovery logic

PWKad/templating,aurelia/templating,hitesh97/templating,shanonvl/aurelia-templating,cmichaelgraham/templating,michaelgeorgeattard/templating,simudream/templating,charlespockert/templating,tcollard/templating,davismj/templating,aurelia/templating,AshleyGrant/templating,milunka/aurelia-templating,JeroenVinke/templating