Only query team tables if repository is under org when getting assignees (#32414)

It's unnecessary to query the team table if the repository is not under
organization when getting assignees.

models/repo/user_repo.go

@@ -110,26 +110,28 @@ func GetRepoAssignees(ctx context.Context, repo *Repository) (_ []*user_model.Us
 		return nil, err
 	}
 
-	additionalUserIDs := make([]int64, 0, 10)
-	if err = e.Table("team_user").
-		Join("INNER", "team_repo", "`team_repo`.team_id = `team_user`.team_id").
-		Join("INNER", "team_unit", "`team_unit`.team_id = `team_user`.team_id").
-		Where("`team_repo`.repo_id = ? AND (`team_unit`.access_mode >= ? OR (`team_unit`.access_mode = ? AND `team_unit`.`type` = ?))",
-			repo.ID, perm.AccessModeWrite, perm.AccessModeRead, unit.TypePullRequests).
-		Distinct("`team_user`.uid").
-		Select("`team_user`.uid").
-		Find(&additionalUserIDs); err != nil {
-		return nil, err
-	}
-
 	uniqueUserIDs := make(container.Set[int64])
 	uniqueUserIDs.AddMultiple(userIDs...)
-	uniqueUserIDs.AddMultiple(additionalUserIDs...)
+
+	if repo.Owner.IsOrganization() {
+		additionalUserIDs := make([]int64, 0, 10)
+		if err = e.Table("team_user").
+			Join("INNER", "team_repo", "`team_repo`.team_id = `team_user`.team_id").
+			Join("INNER", "team_unit", "`team_unit`.team_id = `team_user`.team_id").
+			Where("`team_repo`.repo_id = ? AND (`team_unit`.access_mode >= ? OR (`team_unit`.access_mode = ? AND `team_unit`.`type` = ?))",
+				repo.ID, perm.AccessModeWrite, perm.AccessModeRead, unit.TypePullRequests).
+			Distinct("`team_user`.uid").
+			Select("`team_user`.uid").
+			Find(&additionalUserIDs); err != nil {
+			return nil, err
+		}
+		uniqueUserIDs.AddMultiple(additionalUserIDs...)
+	}
 
 	// Leave a seat for owner itself to append later, but if owner is an organization
 	// and just waste 1 unit is cheaper than re-allocate memory once.
 	users := make([]*user_model.User, 0, len(uniqueUserIDs)+1)
-	if len(userIDs) > 0 {
+	if len(uniqueUserIDs) > 0 {
 		if err = e.In("id", uniqueUserIDs.Values()).
 			Where(builder.Eq{"`user`.is_active": true}).
 			OrderBy(user_model.GetOrderByName()).