⚰️ Delete dead code

Author: sergei-maertens

src/openforms/scss/_vars.scss

@@ -34,10 +34,4 @@ $django-hijack-yellow: #ffe761;
   --of-admin-tooltip-border-color: #f7f071;
   --of-admin-tooltip-color: #000;
   --of-admin-tooltip-size: 14px;
-
-  /* JSON DSL preview */
-  --of-admin-json-preview-rows: 10;
-
-  /* JSON Widget */
-  --of-admin-json-widget-rows: 8;
 }

src/openforms/scss/components/admin/_json-editor.scss

@@ -8,7 +8,7 @@
 
   min-inline-size: var(
     --of-json-widget-min-inline-size,
-    // assume monospace font, multiple the width of one char times the number of cols requested
+    // assume monospace font, multiply the width of one char times the number of cols requested
     // and add the space for the editor margin
     calc(
         var(--of-json-widget-cols, 10) * var(--of-json-widget-char-size, 8.44px) +