[submodule] Update submodule sonic-snmpagent to the latest HEAD automatically (sonic-net#21420)

#### Why I did it
src/sonic-snmpagent
```
* 9e2c50a - (HEAD -> master, origin/master, origin/HEAD) Fix snmp agent not-responding issue when high CPU utilization (sonic-net#345) (2 hours ago) [Jianquan Ye]
```
#### How I did it
#### How to verify it
#### Description for the changelog

Author: mssonicbld