fix: remove imports breaking build

[KristinAoki]

This PR removes paragon scss variable imports from .scss files. These imports break the build of the course authoring MFE because of a ModuleErrorBuild. The only variable used is $gray-500 and the hex code for the variable is the same in the openedX and edX themes, #707070, so replacement will have no affect on the UI

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.91%. Comparing base (beb4813) to head (295008e).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #500   +/-   ##
=======================================
  Coverage   88.91%   88.91%           
=======================================
  Files         248      248           
  Lines        4554     4554           
  Branches      943      939    -4     
=======================================
  Hits         4049     4049           
  Misses        472      472           
  Partials       33       33           

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[bradenmacdonald]

If you prefer to keep the variables, I think open-craft@5ff22c1 would fix the error; assuming it's the same as a similar error I recently saw. This fix seems fine too though.