优化默认值的问题，Model中不建议有默认值的逻辑。

Yancey

2022-02-09 6f0c59d7be923b0d94c568fe4ba6280ede89f10b

 ruoyi-ui/src/views/system/menu/index.vue

@@ -128,7 +128,7 @@
            </el-form-item>
          </el-col>
          <el-col :span="24" v-if="form.menuType != 'F'">
            <el-form-item label="菜单图标">
            <el-form-item label="菜单图标" prop="icon">
              <el-popover
                placement="bottom-start"
                width="460"