fix: 修复预览点击禁用后无效的bug。

src/components/VueFormMaking/components/GenerateFormItem.vue

@@ -357,9 +357,7 @@ export default {
       })
     }
 
-    if (this.disabled === undefined || this.disabled === null) {
-      this.widget.options.disabled = false
-    } else {
+    if (this.disabled !== undefined && this.disabled !== null) {
       this.widget.options.disabled = this.disabled
     }