chore: improve error message on failed SMApp register/unregister (#42557

)

Co-authored-by: trop[bot] <37223003+trop[bot]@users.noreply.github.com>
Co-authored-by: Shelley Vohr <[email protected]>

shell/common/platform_util_mac.mm

@@ -111,7 +111,7 @@
  return "The specified path doesn't exist or the helper tool at the "
  "specified path isn't valid";
  default:
- return "Failed to register the login item";
+ return base::SysNSStringToUTF8([error localizedDescription]);
  }
  }