dcsctp: Don't send FORWARD-TSN in its own chunk

This is a rollback of a change list [1] that was an attempt to avoid a
bug in usrsctp[2], but it wasn't very successful. But with the usrsctp
bug fixed, we can revert to the desired state; that we bundle
FORWARD-TSN with other control and data chunks in a SCTP packet.

[1] https://webrtc-review.googlesource.com/c/src/+/229101
[2] https://github.com/sctplab/usrsctp/issues/597

Bug: webrtc:42223134
Change-Id: I2f3b511c91639e6b9516160190600beb0c04b5fa
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/361862
Reviewed-by: Florent Castelli <orphis@webrtc.org>
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#42976}
diff --git a/net/dcsctp/socket/transmission_control_block.cc b/net/dcsctp/socket/transmission_control_block.cc
index 26ca6f6..38913e6 100644
--- a/net/dcsctp/socket/transmission_control_block.cc
+++ b/net/dcsctp/socket/transmission_control_block.cc
@@ -169,7 +169,6 @@
     } else {
       builder.Add(retransmission_queue_.CreateForwardTsn());
     }
-    Send(builder);
     // https://datatracker.ietf.org/doc/html/rfc3758
     // "IMPLEMENTATION NOTE: An implementation may wish to limit the number of
     // duplicate FORWARD TSN chunks it sends by ... waiting a full RTT before