Reverted to default font because of Element bug

As of now Element harcodes the default font in all custom themes: https://github.com/matrix-org/matrix-react-sdk/blob/develop/res/themes/light-custom/css/light-custom.scss#L3. This prevents adding custom fonts to custom themes. Another Element bug ([Issue #15095](element-hq/element-web#15095)) replaces the default font Inter with the previous default Nunito. We expect to add custom fonts once this is resolved.

Discord/Discord-Dark/Discord-Dark-Theme.json

@@ -1,15 +1,6 @@
 {
     "name": "Discord Dark",
     "is_dark": true,
-    "fonts": {
-         "faces": [
-             {
-                  "font-family": "Inter",
-                  "src": [{"url": "/fonts/Inter.ttf", "format": "ttf"}]
-             }
-         ],
-         "general": "Inter, sans",
-         "monospace": "'Courier New'"
     "colors": {
         "accent-color": "#5865F2",
         "primary-color": "#00aff4",