fix： 修改panel 无法切换的问题 以及 表达式的隐藏

nezha-fronted/src/components/page/dashboard/panel.vue

@@ -348,7 +348,7 @@ export default {
       this.filter.searchName = ''
       // this.$refs.searchInput.select();
       this.showPanel = val
-      this.variables = this.showPanel.param.variables
+      this.variables = this.$loadsh.get(this, 'showPanel.param.variables', []) || []
       this.showPanel.type = 'dashboard'
       this.filter.panelId = this.showPanel.id
       this.panelId = this.showPanel.id
@@ -785,7 +785,7 @@ export default {
             this.$message.error(response)
           }
         }
-        this.variables = this.showPanel.param.variables
+        this.variables = this.$loadsh.get(this, 'showPanel.param.variables', []) || []
       }).catch((error) => {
         // console.log('error................'+JSON.stringify(error));
         if (error) {