chore: fix sass deprecation with mixed declaration in nested rules

[ShGKme]

See: https://sass-lang.com/documentation/breaking-changes/mixed-decls/

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 23.54%. Comparing base (df34ac0) to head (d039b91).
Report is 8 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #6406   +/-   ##
=========================================
  Coverage     23.54%   23.54%           
  Complexity      454      454           
=========================================
  Files           247      247           
  Lines         11701    11701           
  Branches       2202     2213   +11     
=========================================
  Hits           2755     2755           
+ Misses         8626     8625    -1     
- Partials        320      321    +1     

Flag	Coverage Δ
javascript	15.07% <ø> (ø)
php	59.53% <ø> (ø)

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