[Sync EN] SNMP: add changelog for PHP 8.5 ValueError validation

PR: `https://github.com/php/doc-en/pull/5533` (2026-05-04)

**Archivos ES a actualizar**
- `reference/snmp/functions/snmp2-get.xml`
- `reference/snmp/functions/snmp2-set.xml`
- `reference/snmp/functions/snmp3-get.xml`
- `reference/snmp/functions/snmp3-set.xml`
- `reference/snmp/functions/snmpget.xml`
- `reference/snmp/functions/snmpset.xml`

