[Stream] New live webhook for missing sub (#21809)

Author: tsmith512

src/content/docs/stream/stream-live/webhooks.mdx

@@ -47,10 +47,11 @@ If there are issues detected with the input, the `event_type` will be `live_inpu
 
 ## Error codes
 
-* `ERR_STORAGE_QUOTA_EXHAUSTED` – The account storage quota has been exceeded.
 * `ERR_GOP_OUT_OF_RANGE` – The input GOP size or keyframe interval is out of range.
 * `ERR_UNSUPPORTED_VIDEO_CODEC` – The input video codec is unsupported for the protocol used.
 * `ERR_UNSUPPORTED_AUDIO_CODEC` – The input audio codec is unsupported for the protocol used.
+* `ERR_STORAGE_QUOTA_EXHAUSTED` – The account storage quota has been exceeded. Delete older content or purcahse additional storage.
+* `ERR_MISSING_SUBSCRIPTION` – Unauthorized to start a live stream. Check subscription or log into Dash for details.
 
 ```json title="Example live_input.errored webhook payload"
 {