Provide better error code for using interaction webhooks before acknowledgement

[MinnDevelopment]

When an application does not acknowledge an application by using the /callback endpoint, the webhook endpoints for followup edits / deletes / sends fail with the response code UNKNOWN_WEBHOOK.

I think the developer experience would be improved significantly, if this error would indicate that the webhook does not work without acknowledging the interaction. I think there already is logic in place to stall the request for 3 seconds, so changing the error for this should be possible.