Fix embedded image cid for named senders with a 'from' address like 'Sender <noreply@sender.com>'

[StefanVietze]

I was struggeling with embedding an image in an html mail body. The picture was attached however it didn't show up in Outlook.

The issue was caused by the sender address which was something like 'AnyFancyName email@address.com'. To be precise the issue is caused by the '>' at the end of the string which survives with your current split logic and causes the cid to have two '>' characters at the end.

I would suggest to use parseaddr function from email.utils to get the raw email address from the msg['from'] field.

[Miksus]

Thanks for pointing this out and making a fix! This indeed seems sensible. I'll try tomorrow to test this myself as well so I get gasp on how the issue actually looks like (and possibly make a test case for this), and then I'll merge this PR.

[codecov-commenter]

Codecov Report

Merging #33 (0449b6d) into master (87c255e) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master      #33   +/-   ##
=======================================
  Coverage   99.48%   99.48%           
=======================================
  Files          13       13           
  Lines         584      584           
=======================================
  Hits          581      581           
  Misses          3        3           

Impacted Files	Coverage Δ
redmail/email/body.py	100.00% <100.00%> (ø)

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[Miksus]

Yep, I now realized what you meant the issue was. Interestingly, it seems Gmail is able to display the image correctly but Outlook does not even though the embedding of CID is indeed wrong. Thanks again for the fix.

I'll try to release a patch about this in the current week.