disable tab remove when tab disabled (#4042)

* when tab  is disabled, disable remove handle.

* disable remove when tab disabled

packages/tabs/src/tabs.vue

@@ -47,6 +47,7 @@
         this.$emit('tab-click', tab, event);
       },
       handleTabRemove(pane, ev) {
+        if (pane.disabled) return;
         ev.stopPropagation();
         this.$emit('edit', pane.name, 'remove');
         this.$emit('tab-remove', pane.name);