Clarify RTO20e1 error message

Address ably/specification#419 (comment)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: lawrence-forooghian

src/plugins/liveobjects/realtimeobject.ts

@@ -240,7 +240,7 @@ export class RealtimeObject {
   /** @spec RTO20e1 */
   private _failPendingOperations(state: ChannelState): void {
     const err = new this._client.ErrorInfo(
-      `objects sync could not be completed due to the channel entering the ${state} state`,
+      `the operation could not be applied locally due to the channel entering the ${state} state whilst waiting for objects sync to complete`,
       92008,
       400,
       this._channel.errorReason || undefined,