[submodule] Update submodule sonic-swss to the latest HEAD automatica…

…lly (#18847)

#### Why I did it
src/sonic-swss
```
* 2e6c5b20 - (HEAD -> master, origin/master, origin/HEAD) [DropCounter]Fix the ordering issue with dropcounter (#3128) (4 hours ago) [Sudharsan Dhamal Gopalarathnam]
```
#### How I did it
#### How to verify it
#### Description for the changelog