#### Why I did it
To fix the logic introduced by [[memory_checker] Do not check memory usage of containers which are not created #11129](https://github.com/sonic-net/sonic-buildimage/pull/11129).
There could be a scenario before the reboot, where
1. The `docker service` has stopped
2. In a very short period of time, the monit service performs the `root@sonic:/home/admin# monit status container_memory_telemetry`
In such scenario, the `memory_checker` script will throw an error to the syslog:
```
ERR memory_checker: Failed to retrieve the running container list from docker daemon! Error message is: 'Error while fetching server API version: ('Connection aborted.', FileNotFoundError(2, 'No such file or directory'))'
```
But, actually, this scenario is a correct behavior, because when the docker service is stopped, the Unix socket is destroyed and that is why we could see the `FileNotFoundError(2, 'No such file or directory'` exception in the syslog.
#### How I did it
Change the log severity to the warning and changed the return value.
#### How to verify it
It is really hard to catch the exact moment described in the `Why I did it` section.
In order to check the logic:
1. Change the Unix socket path to non-existing in [/usr/bin/memory_checker](47742dfc2c/files/image_config/monit/memory_checker (L139)) file on the switch.
2. Execute the `root@sonic:/home/admin# monit restart container_memory_telemetry`
3. Check the syslog for such messages:
```
WARNING memory_checker: Failed to retrieve the running container list from docker daemon! Error message is: 'Error while fetching server API version: ('Connection aborte
d.', FileNotFoundError(2, 'No such file or directory'))'
INFO memory_checker: [memory_checker] Exits without checking memory usage since container 'telemetry' is not running!
```
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