Allow contact_info field to be nullable to match stova event data

[DeanElliott96]

Description of change

This field is null from Stova and is not required by Data Hub so allow it to be null as well.

Checklist

• Has this branch been rebased on top of the current main branch?
• Is the CircleCI build passing?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.63%. Comparing base (9b2789f) to head (2fb3b87).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5978   +/-   ##
=======================================
  Coverage   96.63%   96.63%           
=======================================
  Files        1083     1084    +1     
  Lines       25410    25414    +4     
  Branches     1678     1678           
=======================================
+ Hits        24555    24559    +4     
  Misses        698      698           
  Partials      157      157           

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[code-review-doctor]

Worth considering. View full project report here.