[ASAP-679] - update engagement calculation & tests

[AkosuaA]

ref: https://asaphub.atlassian.net/browse/ASAP-679

• Filtered out cancelled events
• The inflated numbers in the Total Speakers column was because there are Event Speakers linked to the teams that do not have events attached.

To fix that I only count speakers when there is an event attached.

• There are two cases where a user that is not onboarded is a speaker. I now exclude event speakers where the user is not onboarded.
• The Events column previously counted both Past & Upcoming Events. It should count only events in the Past Event column https://asaphub.atlassian.net/browse/ASAP-679?focusedCommentId=11807

Current results computed for Prod can be found in this sheet https://docs.google.com/spreadsheets/d/1iGTVBmsXe58qWwS6_zPlIAWEKwZ9mw2v9kfM4S8ijV4/edit?usp=sharing

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.45%. Comparing base (d5e5665) to head (c37e7e4).
Report is 4 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #4380   +/-   ##
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  Coverage   99.45%   99.45%           
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  Files        1050     1050           
  Lines       20119    20126    +7     
  Branches     6327     6331    +4     
=======================================
+ Hits        20010    20017    +7     
  Misses        109      109           

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