fix: postgres config check logic

Co-authored-by: Copilot <[email protected]>

Author: leggetter

internal/logstore/logstore.go

@@ -66,7 +66,7 @@ func MakeDriverOpts(cfg Config) (DriverOpts, error) {
 	// 	driverOpts.CH = chDB
 	// }
 
-	if cfg.Postgres != nil || *cfg.Postgres != "" {
+	if cfg.Postgres != nil && *cfg.Postgres != "" {
 		pgDB, err := pgxpool.New(context.Background(), *cfg.Postgres)
 		if err != nil {
 			return DriverOpts{}, err