update Admin.NET/Admin.NET.Core/Entity/SysMenu.cs.

先去除唯一索引，按钮权限Name值为NULL不支持补加唯一索引；换成初始化seeddata前代码判断

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

Admin.NET/Admin.NET.Core/Entity/SysMenu.cs

@@ -13,7 +13,6 @@ namespace Admin.NET.Core;
 [SysTable]
 [SugarIndex("index_{table}_T", nameof(Title), OrderByType.Asc)]
 [SugarIndex("index_{table}_T2", nameof(Type), OrderByType.Asc)]
-[SugarIndex("index_{table}_T3", nameof(Name), OrderByType.Asc, IsUnique = true)]
 public partial class SysMenu : EntityBase
 {
     /// <summary>