Track stream object IDs correctly.

From MOQT interop: the stream tracks next_object_. After sending, it should update to sent_object + 1, not just increment by 1. When object IDs are not sequential on the stream it sends the same object multiple times, triggering QUICHE_BUG.

PiperOrigin-RevId: 842798573

quiche/quic/moqt/moqt_session.cc

diff --git a/quiche/quic/moqt/moqt_session.cc b/quiche/quic/moqt/moqt_session.cc
index da5f699..2b34f55 100644
--- a/quiche/quic/moqt/moqt_session.cc
+++ b/quiche/quic/moqt/moqt_session.cc
@@ -2474,8 +2474,8 @@
       // there is no need to process the stream any further.
       return;
     }
-    ++next_object_;
     last_object_id_ = object->metadata.location.object;
+    next_object_ = *last_object_id_ + 1;
     subscription.OnObjectSent(object->metadata.location);
 
     if (object->fin_after_this && !delivery_timeout.IsInfinite() &&