Use static font name instead of variable when loading fonts, because changing the variable's value (e.g. in a child theme) can result in loading open sans under a wrong name

Author: woutk88

app/design/frontend/Magento/blank/web/css/source/_typography.less

@@ -9,31 +9,31 @@
 
 & when (@media-common = true) {
     .lib-font-face(
-        @family-name: @font-family-name__base,
+        @family-name: 'Open Sans',
         @font-path: '@{baseDir}fonts/opensans/light/opensans-300',
         @font-weight: 300,
         @font-style: normal,
         @font-display: swap
     );
 
     .lib-font-face(
-        @family-name: @font-family-name__base,
+        @family-name: 'Open Sans',
         @font-path: '@{baseDir}fonts/opensans/regular/opensans-400',
         @font-weight: 400,
         @font-style: normal,
         @font-display: swap
     );
 
     .lib-font-face(
-        @family-name: @font-family-name__base,
+        @family-name: 'Open Sans',
         @font-path: '@{baseDir}fonts/opensans/semibold/opensans-600',
         @font-weight: 600,
         @font-style: normal,
         @font-display: swap
     );
 
     .lib-font-face(
-        @family-name: @font-family-name__base,
+        @family-name: 'Open Sans',
         @font-path: '@{baseDir}fonts/opensans/bold/opensans-700',
         @font-weight: 700,
         @font-style: normal,