Node icon fixes

components/lib/tree/TreeNode.vue

@@ -26,7 +26,7 @@
                     <component v-else :is="checked ? 'CheckIcon' : partialChecked ? 'MinusIcon' : null" :class="cx('checkboxIcon')" v-bind="getPTOptions('checkboxIcon')" />
                 </div>
             </div>
-            <span :class="cx('nodeIcon')" v-bind="getPTOptions('nodeIcon')"></span>
+            <span :class="[cx('nodeIcon'), node.icon]" v-bind="getPTOptions('nodeIcon')"></span>
             <span :class="cx('label')" v-bind="getPTOptions('label')" @keydown.stop>
                 <component v-if="templates[node.type] || templates['default']" :is="templates[node.type] || templates['default']" :node="node" />
                 <template v-else>{{ label(node) }}</template>

components/lib/tree/style/TreeStyle.js

@@ -122,7 +122,7 @@ const classes = {
         }
     ],
     checkboxIcon: 'p-checkbox-icon',
-    nodeIcon: ({ instance }) => ['p-treenode-icon', instance.node.icon],
+    nodeIcon: 'p-treenode-icon',
     label: 'p-treenode-label',
     subgroup: 'p-treenode-children'
 };