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

…lly (#18824)

#### Why I did it
src/sonic-gnmi
```
* 530c6bb - (HEAD -> 202311, origin/202311) Merge pull request #220 from sonic-net/revert-211-cherry/202311/173 (3 days ago) [Ying Xie]
* db6f983 - (origin/revert-211-cherry/202311/173) Revert "Replace PFC_WD_TABLE with PFC_WD (#173)" (8 days ago) [Zain Budhwani]
```
#### How I did it
#### How to verify it
#### Description for the changelog