[submodule] Update submodule sonic-restapi to the latest HEAD automatically (#16871)

#### Why I did it
src/sonic-restapi
```
* c8fa96b - (HEAD -> master, origin/master, origin/HEAD) Remove command to install libhiredis deb file (#146) (23 hours ago) [Saikrishna Arcot]
```
#### How I did it
#### How to verify it
#### Description for the changelog

Author: mssonicbld