[GIT-PULLS] [php-src] PR #23480: ext/pgsql: stop advertising PGSQL_DML_ASYNC where it is refused

Pull Request: https://github.com/php/php-src/pull/23480
Author: lacatoire

`pg_update()` and `pg_delete()` reject `PGSQL_DML_ASYNC` in their option mask but then name it in the error message as an accepted flag:

```c
if (option & ~(PGSQL_CONV_OPTS|PGSQL_DML_NO_CONV|PGSQL_DML_EXEC|PGSQL_DML_STRING|PGSQL_DML_ESCAPE)) {
    zend_argument_value_error(5, "must be a valid bit mask of PGSQL_CONV_FORCE_NULL, PGSQL_DML_NO_CONV, "
        "PGSQL_DML_ESCAPE, PGSQL_DML_EXEC, PGSQL_DML_ASYNC, and PGSQL_DML_STRING");
```

The fix removes `PGSQL_DML_ASYNC` from the two error messages. `pg_insert()` and `pg_select()` accept the flag and keep their existing wording unchanged.

A second defect is fixed in the same file: the `ZEND_ASSERT` inside `php_pgsql_delete()` excluded `PGSQL_DML_NO_CONV`, but its caller `pg_delete()` accepts that bit and passes it through untouched — the helper consults it four lines below the assert. The assert is widened to match the actual accepted mask.

A new test (`ext/pgsql/tests/pg_dml_option_flags.phpt`) covers the corrected error messages and the `pg_delete()`/`PGSQL_DML_NO_CONV` path.