remove(variables). refs #6486 remove old variables

src/css/quasar.variables.scss

@@ -12,8 +12,6 @@
 // to match your app's branding.
 // Tip: Use the "Theme Builder" on Quasar's documentation website.
 // Tip: to add new colors https://quasar.dev/style/color-palette/#adding-your-own-colors
-$dark-theme: true !default;
-$light-theme: true !default;
 $primary: #ec8916;
 $secondary: $primary;
 $positive: #21ba45;