[submodule] Update submodule linkmgrd to the latest HEAD automatically (#21104)

#### Why I did it
src/linkmgrd
```
* ccd52d0 - (HEAD -> master, origin/master, origin/HEAD) Enforce switchover when target state is `standby` AND mux mode is `standby` (#281) (26 hours ago) [Jing Zhang]
```
#### How I did it
#### How to verify it
#### Description for the changelog

Author: mssonicbld