Fix admin team access mode value in team_unit table (#24012)

Same as https://github.com/go-gitea/gitea/pull/23675
Feedback:
https://github.com/go-gitea/gitea/pull/23879#issuecomment-1500923636

models/migrations/migrations.go

@@ -481,6 +481,8 @@ var migrations = []Migration{
 	NewMigration("Change Container Metadata", v1_20.ChangeContainerMetadataMultiArch),
 	// v251 -> v252
 	NewMigration("Fix incorrect owner team unit access mode", v1_20.FixIncorrectOwnerTeamUnitAccessMode),
+	// v252 -> v253
+	NewMigration("Fix incorrect admin team unit access mode", v1_20.FixIncorrectAdminTeamUnitAccessMode),
 }
 
 // GetCurrentDBVersion returns the current db version

models/migrations/v1_20/v252.go

@@ -0,0 +1,47 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package v1_20 //nolint
+
+import (
+	"code.gitea.io/gitea/modules/log"
+
+	"xorm.io/xorm"
+)
+
+func FixIncorrectAdminTeamUnitAccessMode(x *xorm.Engine) error {
+	type UnitType int
+	type AccessMode int
+
+	type TeamUnit struct {
+		ID         int64    `xorm:"pk autoincr"`
+		OrgID      int64    `xorm:"INDEX"`
+		TeamID     int64    `xorm:"UNIQUE(s)"`
+		Type       UnitType `xorm:"UNIQUE(s)"`
+		AccessMode AccessMode
+	}
+
+	const (
+		// AccessModeAdmin admin access
+		AccessModeAdmin = 3
+	)
+
+	sess := x.NewSession()
+	defer sess.Close()
+
+	if err := sess.Begin(); err != nil {
+		return err
+	}
+
+	count, err := sess.Table("team_unit").
+		Where("team_id IN (SELECT id FROM team WHERE authorize = ?)", AccessModeAdmin).
+		Update(&TeamUnit{
+			AccessMode: AccessModeAdmin,
+		})
+	if err != nil {
+		return err
+	}
+	log.Debug("Updated %d admin team unit access mode to belong to admin instead of none", count)
+
+	return sess.Commit()
+}