remove newlines before b64decode

[maraspr]

Fix for errors in parsing b64-strings caused by PR-648.
This removes newlines before trying b64decode, since b64decode with validate=True does not accept any characters that are not in the base64 alphabet (even newlines).

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 60.00%. Comparing base (f618f69) to head (87ebbdb).
⚠️ Report is 251 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #649      +/-   ##
==========================================
+ Coverage   58.39%   60.00%   +1.61%     
==========================================
  Files          12       12              
  Lines        1620     2038     +418     
==========================================
+ Hits          946     1223     +277     
- Misses        674      815     +141     

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