feat(checkbox): update fluent tick width

Author: adrianptrv

projects/igniteui-angular/src/lib/core/styles/components/checkbox/_checkbox-theme.scss

@@ -51,7 +51,7 @@
 
     $mark-stroke: map.get((
         'material': 3,
-        'fluent': 1,
+        'fluent': 1.5,
         'bootstrap': 3,
         'indigo': 3,
     ), $variant);