Make sure media transport is deleted before ICE.

This was regression due to
https://webrtc-review.googlesource.com/c/src/+/111920

which broke downstream projects. The break was not caught in
unit tests, because unit tests use loopback and fake media
transports that do not use ICE.

Bug: None
Change-Id: If95935afed430d62d5ff9a2ee01d8eaccadc198d
Reviewed-on: https://webrtc-review.googlesource.com/c/113440
Commit-Queue: Steve Anton <steveanton@webrtc.org>
Reviewed-by: Peter Slatala <psla@webrtc.org>
Reviewed-by: Steve Anton <steveanton@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25926}
diff --git a/pc/jseptransport.cc b/pc/jseptransport.cc
index 28389d5..eddbbce 100644
--- a/pc/jseptransport.cc
+++ b/pc/jseptransport.cc
@@ -135,6 +135,9 @@
 JsepTransport::~JsepTransport() {
   if (media_transport_) {
     media_transport_->SetMediaTransportStateCallback(nullptr);
+
+    // Make sure we delete media transport before ICE.
+    media_transport_.reset();
   }
   // Clear all DtlsTransports. There may be pointers to these from
   // other places, so we can't assume they'll be deleted by the destructor.