Remove unnecessary code (#32560) (#32567)

Backport #32560 by @lunny

PushMirrors only be used in the repository setting page. So it should
not be loaded on every repository page.

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

services/context/repo.go

@@ -394,14 +394,7 @@ func repoAssignment(ctx *Context, repo *repo_model.Repository) {
 		}
 	}
 
-	pushMirrors, _, err := repo_model.GetPushMirrorsByRepoID(ctx, repo.ID, db.ListOptions{})
-	if err != nil {
-		ctx.ServerError("GetPushMirrorsByRepoID", err)
-		return
-	}
-
 	ctx.Repo.Repository = repo
-	ctx.Data["PushMirrors"] = pushMirrors
 	ctx.Data["RepoName"] = ctx.Repo.Repository.Name
 	ctx.Data["IsEmptyRepo"] = ctx.Repo.Repository.IsEmpty
 }