HalfClosedLocalToClosed: give ACK and stream distinct PNs

Summary:
The ACK used pre-increment and the stream packet used post-increment, so both ended up with the same packet number. D104911111 drops duplicates per RFC 9000 12.3, so the stream frame is no longer processed and readAvailable never fires.

Use pre-increment for the stream packet, matching the convention used by the other ACK + stream pairs in this file.

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overriding_review_checks_triggers_an_audit_and_retroactive_review
Oncall Short Name: traffic_protocols

landed-with-radar-review

Differential Revision: D105880715

fbshipit-source-id: 69efdacaeda01db950ce2fc809a225142070a760

Author: jbeshay

quic/fizz/client/test/QuicClientTransportTest.cpp

@@ -4855,7 +4855,7 @@ TEST_F(QuicClientTransportAfterStartTest, HalfClosedLocalToClosed) {
   auto packet = packetToBuf(createStreamPacket(
       *serverChosenConnId /* src */,
       *originalConnId /* dest */,
-      appDataPacketNum++,
+      ++appDataPacketNum,
       streamId,
       *data,
       0 /* cipherOverhead */,