Explicitly not update indexes when sync database schemas (#34281)

Fix #34275

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Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

models/migrations/v1_24/v318.go

@@ -13,5 +13,9 @@ func AddRepoUnitAnonymousAccessMode(x *xorm.Engine) error {
 	type RepoUnit struct { //revive:disable-line:exported
 		AnonymousAccessMode perm.AccessMode `xorm:"NOT NULL DEFAULT 0"`
 	}
-	return x.Sync(&RepoUnit{})
+	_, err := x.SyncWithOptions(xorm.SyncOptions{
+		IgnoreConstrains: true,
+		IgnoreIndices:    true,
+	}, new(RepoUnit))
+	return err
 }