Fixes for Aviti demux emails

[ssjunnebo]

• Correction of the URL in transfer email
• Send an email if the MismatchThreshold is set to 0 to make sure we don't miss informing the user about it

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 26.14%. Comparing base (ccccad2) to head (3e58339).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #500      +/-   ##
==========================================
+ Coverage   26.07%   26.14%   +0.07%     
==========================================
  Files          37       37              
  Lines        5581     5587       +6     
==========================================
+ Hits         1455     1461       +6     
  Misses       4126     4126              

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[FranBonath]

I think this would send the email even if the mismatch threshold was predetermined to be 0 and there is no index collision (for example when we only have single indexes.

[ssjunnebo]

Hm, I can't see that it does that anywhere. I'm not sure it would send it for those cases anyway, since i1_mm_threshold and i2_mm_threshold come from get_custom_mistmatch_thresholds that only looks at the distance.

[aanil]

Code looks ok 👍