[improve](postgresql catalog) support postgresql bytea type to doris string (#18623)

* [improve](postgresql catalog) support postgresql bytea type to doris string

* modify function name

* add case

fe/fe-core/src/main/java/org/apache/doris/external/jdbc/JdbcClient.java

@@ -586,6 +586,7 @@ public class JdbcClient {
             case "varbit":
             case "jsonb":
             case "uuid":
+            case "bytea":
                 return ScalarType.createStringType();
             default:
                 return Type.UNSUPPORTED;