Added missing check in List component for if items exist

• Added:
- missing check in List component for if items exist

app/javascript/gabsocial/components/list.js

@@ -36,6 +36,7 @@ class List extends ImmutablePureComponent {
           placeholderCount={12}
         >
           {
+            !!items && itemsSize > 0 &&
             items.map((item, i) => (
               <ListItem
                 size={size}