FIX: allows forcing unsafe string in select-kit (#6386)

forceEscape will be defaulted to true before next release.

app/assets/javascripts/select-kit/components/multi-select.js.es6

@@ -31,12 +31,9 @@ export default SelectKitComponent.extend({
       this.set("values", []);
     }
 
-    this.set(
-      "headerComponentOptions",
-      Ember.Object.create({
-        selectedNameComponent: this.get("selectedNameComponent")
-      })
-    );
+    this.get("headerComponentOptions").setProperties({
+      selectedNameComponent: this.get("selectedNameComponent")
+    });
   },
 
   @on("didRender")