tests: update Traefik's service tests

The test was based on an old implementation, before the introduction of
the `runagent` command.

tests/00_traefik.robot

@@ -3,7 +3,7 @@ Library    SSHLibrary
 
 *** Test Cases ***
 Check if traefik service is loaded correctly
-    ${output}  ${rc} =    Execute Command    ssh -o StrictHostKeyChecking=no traefik1@localhost systemctl --user show --property=LoadState traefik
+    ${output}  ${rc} =    Execute Command    runagent -m traefik1 systemctl --user show --property=LoadState traefik
     ...    return_rc=True
     Should Be Equal As Integers    ${rc}  0
     Should Be Equal As Strings    ${output}    LoadState=loaded