[submodule] Update submodule dhcpmon to the latest HEAD automatically (sonic-net#22652)

#### Why I did it
src/dhcpmon
```
* c7f2169 - (HEAD -> master, origin/master, origin/HEAD) Add support for clear per-interface counter (sonic-net#39) (19 hours ago) [Yaqiang Zhu]
* ee55c11 - [build] Update to ubuntu 24.04 in build pipeline (sonic-net#40) (3 days ago) [Yaqiang Zhu]
```
#### How I did it
#### How to verify it
#### Description for the changelog

Author: mssonicbld