fix: apply suggestions from code review

Co-authored-by: ZHANG Yuntian <[email protected]>

src/usr/lib/rsetup/tui/system/system.sh

@@ -74,7 +74,7 @@ __system_bootloader_helper() {
  return
  fi
 
- if __external_script_type_check "/usr/lib/u-boot/$bootloader/setup.sh" "$bootloader_method" "function" 2>/dev/null && \
+ if __external_script_type_check "/usr/lib/u-boot/$bootloader/setup.sh" "$bootloader_method" "function" && \
  "$bootloader_method" "$bootloader"
  then
  msgbox "The $bootloader_type has been updated successfully."