metrics: Ensure docker is running in init_env

This PR ensures that docker is running as part of the init_env function
in kata metrics to avoid failures like docker is not running and making
the kata metrics CI to fail.

Fixes #7898

Signed-off-by: Gabriela Cervantes <gabriela.cervantes.tellez@intel.com>

tests/metrics/lib/common.bash

@@ -168,6 +168,8 @@ function init_env()
 
 	cmd=("docker" "ctr")
 
+	sudo systemctl restart docker
+
 	# check dependencies
 	check_cmds "${cmd[@]}"