[submodule] Update submodule sonic-gnmi to the latest HEAD automatically (#18823)

#### Why I did it
src/sonic-gnmi
```
* eea5d7d - (HEAD -> master, origin/master, origin/HEAD) Fix memory leak (#223) (2 days ago) [ganglv]
```
#### How I did it
#### How to verify it
#### Description for the changelog

Author: mssonicbld