[management] Close the cloned test store when seeding it fails

The Postgres and MySQL test constructors opened the store and then
returned an error from SaveInstallationID or SaveAccount without
closing it, leaking the connection and the pgx pool. Both now share one
seeding helper and release the store on that path.

management/server/store/sql_store.go

@@ -3222,18 +3222,11 @@ func newPostgresqlStoreFromSqlStore(ctx context.Context, sqliteStore *SqlStore,
 		return nil, err
 	}
 
-	err = store.SaveInstallationID(ctx, sqliteStore.GetInstallationID())
-	if err != nil {
+	if err := seedFromSqliteStore(ctx, store, sqliteStore); err != nil {
+		closeStore(ctx, store)
 		return nil, err
 	}
 
-	for _, account := range sqliteStore.GetAllAccounts(ctx) {
-		err := store.SaveAccount(ctx, account)
-		if err != nil {
-			return nil, err
-		}
-	}
-
 	return store, nil
 }
 
@@ -3286,24 +3279,40 @@ func NewMysqlStoreFromSqlStore(ctx context.Context, sqliteStore *SqlStore, dsn s
 	return newMysqlStoreFromSqlStore(ctx, sqliteStore, dsn, metrics, false)
 }
 
+// seedFromSqliteStore copies the installation ID and the accounts of the
+// sqlite seed store into a freshly created engine store.
+func seedFromSqliteStore(ctx context.Context, store, sqliteStore *SqlStore) error {
+	if err := store.SaveInstallationID(ctx, sqliteStore.GetInstallationID()); err != nil {
+		return err
+	}
+	for _, account := range sqliteStore.GetAllAccounts(ctx) {
+		if err := store.SaveAccount(ctx, account); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// closeStore releases a store that is not handed to the caller, so a failed
+// seed does not leak its connection and pool.
+func closeStore(ctx context.Context, store *SqlStore) {
+	store.Close(ctx)
+	if store.pool != nil {
+		store.pool.Close()
+	}
+}
+
 func newMysqlStoreFromSqlStore(ctx context.Context, sqliteStore *SqlStore, dsn string, metrics telemetry.AppMetrics, skipMigration bool) (*SqlStore, error) {
 	store, err := NewMysqlStore(ctx, dsn, metrics, skipMigration)
 	if err != nil {
 		return nil, err
 	}
 
-	err = store.SaveInstallationID(ctx, sqliteStore.GetInstallationID())
-	if err != nil {
+	if err := seedFromSqliteStore(ctx, store, sqliteStore); err != nil {
+		closeStore(ctx, store)
 		return nil, err
 	}
 
-	for _, account := range sqliteStore.GetAllAccounts(ctx) {
-		err := store.SaveAccount(ctx, account)
-		if err != nil {
-			return nil, err
-		}
-	}
-
 	return store, nil
 }