Migrate to Sass modules

fix function

scss/_toasts.scss

@@ -1,3 +1,8 @@
+@use "config" as *;
+@use "variables" as *;
+@use "mixins/border-radius" as *;
+@use "vendor/rfs" as *;
+
 .toast {
   // scss-docs-start toast-css-vars
   --#{$prefix}toast-zindex: #{$zindex-toast};