fix(switch): style component using sass themes

Author: SisIvanova

projects/igniteui-angular/src/lib/core/styles/components/switch/_switch-theme.scss

@@ -130,14 +130,12 @@
     %switch-composite--hover {
         border-color: var-get($theme, 'border-hover-color');
 
-        @if $variant != 'material' {
-            %switch-thumb {
-                background: var-get($theme, 'thumb-off-hover-color');
-            }
+        %switch-thumb {
+            background: var-get($theme, 'thumb-off-hover-color');
+        }
 
-            %switch-thumb--x {
-                background: var-get($theme, 'thumb-on-color');
-            }
+        %switch-thumb--x {
+            background: var-get($theme, 'thumb-on-color');
         }
     }
 
@@ -153,10 +151,8 @@
         background: var-get($theme, 'track-on-hover-color');
         border-color: var-get($theme, 'border-on-hover-color');
 
-        @if $variant != 'material' {
-            %switch-thumb {
-                background: var-get($theme, 'thumb-on-color');
-            }
+        %switch-thumb {
+            background: var-get($theme, 'thumb-on-color');
         }
     }