[electrum] delete unused code that raises on linux and windows

Summary: This code is unused and caused an error when running pytest --doctest-modules electrumabc

Test Plan:
pytest --doctest-modules electrumabc

Note that there is still an error in another module, but it no longer fails on qrreaders

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D14469