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

#17820)

#### Why I did it
src/linkmgrd
```
* 74c33ea - (HEAD -> master, origin/master, origin/HEAD) [active-standby] Probe the link in suspend timeout (#235) (12 hours ago) [Longxiang Lyu]
```
#### How I did it
#### How to verify it
#### Description for the changelog