Remove unnecessary qualification.

Author: kevinpschaaf

lib/mixins/element-mixin.js

@@ -778,7 +778,6 @@ export const ElementMixin = dedupingMixin(base => {
       // we don't want to spam existing users who might have adopted the
       // shorthand when attribute deserialization is not important.
       if (legacyOptimizations && !(prop in this._properties) &&
-          effect.info && effect.info.part && 
           !(effect.info.part.signature && effect.info.part.signature.static) &&
           !effect.info.part.hostProp && !templateInfo.nestedTemplate) {
         console.warn(`Property '${prop}' used in template but not declared in 'properties'; ` +