[submodule] Update submodule sonic-gnmi to the latest HEAD automatically (#16228)

#### Why I did it
src/sonic-gnmi
```
* ac94807 - (HEAD -> master, origin/master, origin/HEAD) Support get all with json (#145) (19 hours ago) [ganglv]
```
#### How I did it
#### How to verify it
#### Description for the changelog
This commit is contained in:
mssonicbld 2023-08-22 16:32:26 +08:00 committed by GitHub
parent b214a8a8b6
commit 55fb6d0a5a
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@ -1 +1 @@
Subproject commit fdb94da0ab27c674eb0b17ecd5409b767fac7282 Subproject commit ac94807358fcb3cc2bd61d31dd7fb54425ac998c