Use consistent bash5 style for conditionals and quoting

install/post-install/finished.sh

@@ -13,7 +13,7 @@ echo
 if [[ -f $OMARCHY_INSTALL_LOG_FILE ]] && grep -q "Total:" "$OMARCHY_INSTALL_LOG_FILE" 2>/dev/null; then
   echo
   TOTAL_TIME=$(tail -n 20 "$OMARCHY_INSTALL_LOG_FILE" | grep "^Total:" | sed 's/^Total:[[:space:]]*//')
-  if [ -n "$TOTAL_TIME" ]; then
+  if [[ -n $TOTAL_TIME ]]; then
     echo_in_style "Installed in $TOTAL_TIME"
   fi
 else
@@ -29,7 +29,7 @@ if gum confirm --padding "0 0 0 $((PADDING_LEFT + 32))" --show-help=false --defa
   # Clear screen to hide any shutdown messages
   clear
 
-  if [[ -n "${OMARCHY_CHROOT_INSTALL:-}" ]]; then
+  if [[ -n ${OMARCHY_CHROOT_INSTALL:-} ]]; then
     touch /var/tmp/omarchy-install-completed
     exit 0
   else