Handle cert fingerprints that contain '/'
Handle cert fingerprints that contain '/'

The cert fingerprint emitted by Muon/Electron is base64 encoded [1], so it may contain '/'. I think we were truncating the certificate fingerprint when this was the case, which may have caused the decoding error in #6524.

[1] https://cs.chromium.org/chromium/src/net/base/hash_value.h?q=net::HashValue&sq=package:chromium&l=58

Auditors: da39a3ee5e6b4b0d3255bfef95601890afd80709@darkdh

luixxiul/browser-laptop,diasdavid/browser-laptop,timborden/browser-laptop,timborden/browser-laptop,diasdavid/browser-laptop,diasdavid/browser-laptop,timborden/browser-laptop,diasdavid/browser-laptop,luixxiul/browser-laptop,darkdh/browser-laptop,timborden/browser-laptop,darkdh/browser-laptop,darkdh/browser-laptop,darkdh/browser-laptop,luixxiul/browser-laptop,luixxiul/browser-laptop