feat: 优化主题置顶显示，同时添加模板

Yi.Abp.Net8/module/bbs/Yi.Framework.Bbs.Application/Services/DiscussService.cs

@@ -106,10 +106,7 @@ namespace Yi.Framework.Bbs.Application.Services
             var items = await _forumManager._discussRepository._DbQueryable
                  .WhereIF(!string.IsNullOrEmpty(input.Title), x => x.Title.Contains(input.Title))
                      .WhereIF(input.PlateId is not null, x => x.PlateId == input.PlateId)
-
-
-                     .WhereIF(input.IsTop == true, x => x.IsTop == input.IsTop)
-
+                     .WhereIF(input.IsTop is not null,x=>x.IsTop==input.IsTop)
                      .LeftJoin<UserEntity>((discuss, user) => discuss.CreatorId == user.Id)
                          .LeftJoin<BbsUserExtraInfoEntity>((discuss, user, info) => user.Id == info.UserId)