👽 Update design tokens for v7

See changelog: https://github.com/nl-design-system/utrecht/blob/e4515df1b2193defa20bd8704acc7a9f12d5231e/components/CHANGELOG.md\#700

Author: sergei-maertens

src/community/utrecht/alert.tokens.json

@@ -1,10 +1,8 @@
 {
   "utrecht": {
     "alert": {
+      "column-gap": {"value": "16px"},
       "icon": {
-        "gap": {
-          "value": "16px"
-        },
         "error": {
           "color": {
             "value": "{of.color.danger}"