fix(slide-toggle): fix font sizing for slide toggle to match other in…

…put methods (#10688)

src/lib/slide-toggle/_slide-toggle-theme.scss

@@ -90,6 +90,6 @@
 
 @mixin mat-slide-toggle-typography($config) {
   .mat-slide-toggle-content {
-    @include mat-typography-level-to-styles($config, body-1);
+    font-family: mat-font-family($config);
   }
 }