Use a better API to retrieve the new card position

Fixes #347

client/components/lists/listBody.js

@@ -27,7 +27,7 @@ BlazeComponent.extendComponent({
     const lastCardDom = this.find('.js-minicard:last');
     const textarea = $(evt.currentTarget).find('textarea');
     const title = textarea.val();
-    const position = Blaze.getData(evt.currentTarget).position;
+    const position = this.currentData().position;
     let sortIndex;
     if (position === 'top') {
       sortIndex = Utils.calculateIndex(null, firstCardDom).base;