Webhook API telemetry: Remove properties that do no exist (#3342)

Author: gmourier

learn/resources/telemetry.mdx

@@ -275,3 +275,4 @@ This list is liable to change with every new version of Meilisearch. It's not be
 | `webhooks_created`                   | Number of webhooks created in an instance                                  | `2`
 | `webhooks.updated`                   | Number of times all webhooks in an instance have been updated                                  | `5`
 | `with_vector_filter`                   | `true` when a document fetch request used a vector filter                                  | `false`
+