Change log for ARISTA_SWITCH

Date Changes
2025-10-15 Enhancement:
- event.idm.read_only_udm.additional.fields: Newly mapped `vlan_id` raw log field to `event.idm.read_only_udm.additional.fields`.
- Enhanced date parsing for `event.idm.read_only_udm.metadata.event_timestamp` to add support for "MMM d HH:mm:ss" and "MMM dd HH:mm:ss" date formats.
- Updated syslog grok patterns to parse the raw log field `timestamp` using both `SYSLOGTIMESTAMP` and `TIMESTAMP_ISO8601` patterns.
2024-06-07 Enhancement:
- Added a Grok pattern to parse the new pattern of SYSLOG format logs.
- Mapped "principal_mac" to "principal.mac".
- Mapped "principal_port" to "principal.port".
2024-03-17 Enhancement:
- Added a Grok pattern to parse SYSLOG format logs.
- Mapped "user" to "principal.user.userid".
- Mapped "proto" to "network.application_protocol".
- Mapped "prin_ip" to "principal.ip".
2022-08-03 Newly created parser