bug#70491: system-config-printer once again cannot find cupshelpers

[Athena Martin via Bug reports for GNU Guix]

$ guix shell system-config-printer -- system-config-printer
Traceback (most recent call last):
  File 
"/gnu/store/hk90zfj9gzx4axws9ymzqni2ka7b2pb1-system-config-printer-1.5.16/share/system-config-printer/system-config-printer.py",
 line 76, in <module>
    import cupshelpers
ModuleNotFoundError: No module named 'cupshelpers'

pgpgFCdG8dkwA.pgp
Description: OpenPGP digital signature