Fix an issue from AI review of cl/914368728.

PiperOrigin-RevId: 914911566

quiche/quic/moqt/moqt_track.cc

diff --git a/quiche/quic/moqt/moqt_track.cc b/quiche/quic/moqt/moqt_track.cc
index df1188b..e7278a6 100644
--- a/quiche/quic/moqt/moqt_track.cc
+++ b/quiche/quic/moqt/moqt_track.cc
@@ -247,6 +247,7 @@
     return kPending;
   }
   if (next_object_->payload_length > 0 && payload_.empty()) {
+    need_object_available_callback_ = true;
     return kPending;
   }
   while (!payload_.empty()) {