[submodule] Update submodule sonic-swss-common to the latest HEAD automatically (sonic-net#20910)

#### Why I did it
src/sonic-swss-common
```
* 6bac82b - (HEAD -> master, origin/master, origin/HEAD) Improve memory usage by move ZMQ serialize buffer from ZmqProducerStateTable to ZmqClient (sonic-net#955) (69 minutes ago) [Hua Liu]
```
#### How I did it
#### How to verify it
#### Description for the changelog

Author: mssonicbld