resolved syntax around if condition to check if variable empty

.github/workflows/pr_check_copies.sh

@@ -42,7 +42,7 @@ curr_env=$2
 comp_env=$3
 comp_env2=$4
 
-if [[ -z $4]]; then
+if [[ -z $4 ]]; then
     compare_files "$1" "${path/$curr_env/"$comp_env"}"
 else
     compare_files "$1" "${path/$curr_env/"$comp_env"}" "${path/$curr_env/"$comp_env2"}"