Remove unused strconv import from grace_restart helper

Co-authored-by: Andrew Jackson (Ajax) <snadrus@users.noreply.github.com>

Author: cursoragent

itests/helpers/grace_restart.go

@@ -7,7 +7,6 @@ import (
 	"net/http"
 	"os"
 	"path/filepath"
-	"strconv"
 	"testing"
 	"time"