[submodule] Update submodule linkmgrd to the latest HEAD automatically (

#19672)

#### Why I did it
src/linkmgrd
```
* 8427a89 - (HEAD -> 202311, origin/202311) [active-standby] raising log level to notice for timed oscillation config change (#262) (2 hours ago) [Jing Zhang]
```
#### How I did it
#### How to verify it
#### Description for the changelog