[submodule] Update submodule sonic-mgmt-common to the latest HEAD automatically (sonic-net#18889)

#### Why I did it
src/sonic-mgmt-common
```
* 328d806 - (HEAD -> master, origin/master, origin/HEAD) Release CString memory to fix memory leak (#138) (11 hours ago) [ganglv]
```
#### How I did it
#### How to verify it
#### Description for the changelog

Author: mssonicbld