fix(#I13WRZ): 演示模式下登录设置禁止修改

#Comment
comment #I13WRZ

#Issue
link https://gitee.com/LongbowEnterprise/dashboard/issues?id=I13WRZ

src/admin/Bootstrap.Admin/Views/Admin/Settings.cshtml

@@ -103,6 +103,9 @@
 <div class="card" asp-auth="loginSettings">
     <div class="card-header">登录设置</div>
     <div class="card-body">
+        <div class="alert alert-danger" role="alert" asp-condition="@Model.IsDemo">
+            <span>演示系统禁止更改登录设置</span>
+        </div>
         <div class="form-inline">
             <div class="row">
                 <div class="form-group col-6">
@@ -115,7 +118,7 @@
                 </div>
             </div>
         </div>
-        <div class="modal-footer text-right">
+        <div class="modal-footer text-right" asp-condition="!@Model.IsDemo">
             <button data-method="loginSettings" class="btn btn-secondary" type="button"><i class="fa fa-save"></i><span>保存</span></button>
         </div>
     </div>