Include prediction ID on edit prediction accepted/discarded events (#24480)

This PR updates the edit predictions to include the prediction ID
returned from the server on the resulting telemetry events indicating
whether the prediction was accepted or discarded.

The `prediction_id` on the events can then be correlated with the
`request_id` on the server-side prediction events.

Release Notes:

- N/A

crates/supermaven/src/supermaven_completion_provider.rs

@@ -92,6 +92,7 @@ fn completion_from_diff(
     }
 
     InlineCompletion {
+        id: None,
         edits,
         edit_preview: None,
     }