[submodule] Update submodule sonic-dbsyncd to the latest HEAD automatically (sonic-net#21040)

#### Why I did it
src/sonic-dbsyncd
```
* 7ad34f6 - (HEAD -> master, origin/master, origin/HEAD) [ci] Fix pipeline issue caused by dist upgrade (sonic-net#72) (53 minutes ago) [Liu Shilong]
```
#### How I did it
#### How to verify it
#### Description for the changelog

Author: mssonicbld