[FIX] edit summary
[FIX] edit summary

Default was changed from None to '' in
Ib076abaa58a963634d9ee3d31cd2f05ed878a50b

Bug: T265968
Change-Id: Ie4f824620603b639fb015661523ed0a12f672920

wikimedia/pywikibot-core,wikimedia/pywikibot-core