Apply styles correctly in RadioGroup component

[b-yogesh]

This PR comes from working on the following PR which requires the radio-button group to be styled:
xcube-PR: xcube-dev/xcube#1144

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.70%. Comparing base (96c1ef3) to head (52e1bef).
Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #122   +/-   ##
=======================================
  Coverage   92.70%   92.70%           
=======================================
  Files          86       86           
  Lines        1495     1495           
  Branches      224      224           
=======================================
  Hits         1386     1386           
  Misses         91       91           
  Partials       18       18           

Flag	Coverage Δ
frontend	84.84% <ø> (ø)

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