fix(NcFormGroup): remove margin when no label/description

[ShGKme]

☑️ Resolves

• Must have been a part of (too early merge): feat: add NcFormGroup #7689

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 51.57%. Comparing base (cafd045) to head (81b9082).
⚠️ Report is 30 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #7764   +/-   ##
=======================================
  Coverage   51.57%   51.57%           
=======================================
  Files          96       96           
  Lines        3141     3141           
  Branches      862      863    +1     
=======================================
  Hits         1620     1620           
  Misses       1273     1273           
  Partials      248      248           

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[susnux]

/backport to stable8