Shellcheck screen size

Signed-off-by: Dan Schaper <dan.schaper@pi-hole.net>

automated install/basic-install.sh

@@ -36,8 +36,8 @@ QUERY_LOGGING=true
 
 # Find the rows and columns will default to 80x24 is it can not be detected
 screen_size=$(stty size 2>/dev/null || echo 24 80)
-rows=$(echo $screen_size | awk '{print $1}')
-columns=$(echo $screen_size | awk '{print $2}')
+rows=$(echo "${screen_size}" | awk '{print $1}')
+columns=$(echo "${screen_size}" | awk '{print $2}')
 
 # Divide by two so the dialogs take up half of the screen, which looks nice.
 r=$(( rows / 2 ))