fix: remove CSS custom selector ref for font-family

This commit addresses an issue where the custom web font is not loading
with the recent release of WCSS. The only change from the previous
version and the new version was the inclusion of the CSS custom property
for font name versus allowing the Sass variable render the value in the
output CSS.

Changes to be committed:
modified:   src/_fonts.scss

src/_fonts.scss

@@ -13,7 +13,7 @@
 
 // Auro rule
 @font-face {
-  font-family: var(--ds-asset-font-circular-family-name, $ds-asset-font-circular-family-name);
+  font-family: $ds-asset-font-circular-family-name;
   font-weight: var(--ds-text-heading-display-weight, $ds-text-heading-display-weight);
   font-style: normal;
 
@@ -27,7 +27,7 @@
 /// @example scss - import src file
 ///   @import "./node_modules/@aurodesignsystem/webcorestylesheets/dist/fonts";
 @font-face {
-  font-family: var(--ds-asset-font-circular-family-name, $ds-asset-font-circular-family-name);
+  font-family: $ds-asset-font-circular-family-name;
   font-weight: var(--ds-text-heading-medium-weight, $ds-text-heading-medium-weight);
   font-style: normal;
 
@@ -40,7 +40,7 @@
 /// @example scss - import src file
 ///   @import "./node_modules/@aurodesignsystem/webcorestylesheets/dist/fonts";
 @font-face {
-  font-family: var(--ds-asset-font-circular-family-name, $ds-asset-font-circular-family-name);
+  font-family: $ds-asset-font-circular-family-name;
   font-weight: var(--ds-text-body-default-weight, $ds-text-body-default-weight);
   font-style: normal;