Fix bug on activities (#33008) (#33016)

Backport #33008 by @lunny

A repository with no issue will display a random number on activities
page. This is caused by wrong usage of `And` and `Or`.


![9cdbbf81d50aa5d9bd16604e0dab5eb0](https://github.com/user-attachments/assets/828cebdc-bd35-4716-a58c-c1b43ddf8bf0)

Co-authored-by: Lunny Xiao <[email protected]>

models/activities/repo_activity.go

@@ -16,6 +16,7 @@ import (
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/gitrepo"
 
+	"xorm.io/builder"
 	"xorm.io/xorm"
 )
 
@@ -337,8 +338,10 @@ func newlyCreatedIssues(ctx context.Context, repoID int64, fromTime time.Time) *
 func activeIssues(ctx context.Context, repoID int64, fromTime time.Time) *xorm.Session {
 	sess := db.GetEngine(ctx).Where("issue.repo_id = ?", repoID).
 		And("issue.is_pull = ?", false).
-		And("issue.created_unix >= ?", fromTime.Unix()).
-		Or("issue.closed_unix >= ?", fromTime.Unix())
+		And(builder.Or(
+			builder.Gte{"issue.created_unix": fromTime.Unix()},
+			builder.Gte{"issue.closed_unix": fromTime.Unix()},
+		))
 
 	return sess
 }