[submodule] Update submodule sonic-snmpagent to the latest HEAD automatically (#17859)

#### Why I did it
src/sonic-snmpagent
```
* 2efaf2e - (HEAD -> 202305, origin/202305) Revert "[action] [PR:303] Fix SNMP dropping some of the queue counter when create_only_config_db_buffers is set to true (#303)" (#308) (4 minutes ago) [StormLiangMS]
```
#### How I did it
#### How to verify it
#### Description for the changelog

Author: mssonicbld