fix: update style imports

[alangsto]

COSMO-388

This frontend is not picking up on brand styles in the staging or production environments. This PR updates how the style sheets are imported to better match other MFE's that do properly pick up brand styles (see https://github.com/openedx/frontend-app-learning/blob/bf2f123367047def9928aff3dccb1d087cf12e31/src/index.scss#L1-L4).

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.53%. Comparing base (bf86ca3) to head (f0cb112).
Report is 11 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #32      +/-   ##
==========================================
+ Coverage   77.11%   77.53%   +0.41%     
==========================================
  Files          22       22              
  Lines         319      316       -3     
  Branches       38       38              
==========================================
- Hits          246      245       -1     
+ Misses         70       68       -2     
  Partials        3        3              

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