根节点机构只有一个，不能被修改

Signed-off-by: Lzh666 <422235757@qq.com>

Admin.NET/Admin.NET.Core/Enum/ErrorCodeEnum.cs

@@ -313,6 +313,12 @@ public enum ErrorCodeEnum
     [ErrorCodeItemMetadata("机构不存在")]
     D2011,
 
+    /// <summary>
+    /// 系统默认机构禁止修改
+    /// </summary>
+    [ErrorCodeItemMetadata("系统默认机构禁止修改")]
+    D2012,
+
     /// <summary>
     /// 字典类型不存在
     /// </summary>

Admin.NET/Admin.NET.Core/Service/Org/SysOrgService.cs

@@ -157,8 +157,8 @@ public class SysOrgService : IDynamicApiController, ITransient
     public async Task UpdateOrg(UpdateOrgInput input)
     {
         if (!_userManager.SuperAdmin && input.Pid == 0)
-            throw Oops.Oh(ErrorCodeEnum.D2009);
-
+            throw Oops.Oh(ErrorCodeEnum.D2012);
+            
         if (input.Pid != 0)
         {
             //var pOrg = await _sysOrgRep.GetFirstAsync(u => u.Id == input.Pid);