Run workflows on all PRs

[sjd210]

See isaacphysics/isaac-react-app#2335, except that VRTs are not used in the API so we don't need that logic here. Workflows will run on every PR (but not every push, so only once a PR is created).

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 41.70%. Comparing base (e67dd37) to head (00e524b).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #828   +/-   ##
=======================================
  Coverage   41.70%   41.70%           
=======================================
  Files         550      550           
  Lines       23674    23674           
  Branches     2863     2863           
=======================================
  Hits         9874     9874           
  Misses      12906    12906           
  Partials      894      894           

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