Fixing typo in en.json (#30649)

More info https://translate.mattermost.com/translate/mattermost/server/en/?checksum=09142512528acc2d#comments

server/i18n/en.json

@@ -8474,7 +8474,7 @@
   },
   {
     "id": "model.access_policy.is_valid.id.app_error",
-    "translation": "Invalid policyy id."
+    "translation": "Invalid policy id."
   },
   {
     "id": "model.access_policy.is_valid.imports.app_error",