fix(radio): wrong label margin in fluent theme (#12388)

Co-authored-by: Simeon Simeonoff <[email protected]>

Author: SisIvanova

projects/igniteui-angular/src/lib/core/styles/components/radio/_radio-theme.scss

@@ -77,7 +77,7 @@
     @include css-vars($theme);
     @include scale-in-out($start-scale: .9);
 
-    $label-margin: rem(8px);
+    $label-margin: rem(6px);
 
     $variant: map.get($theme, variant);
     $bootstrap-theme: $variant == 'bootstrap';