bug: segfault in webtransport stream

[p-shahi]

Version: 0.24.1
Seen in kubo0.18-rc1

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x18 pc=0x1b1b0a0]

goroutine 1359646 [running]:
github.com/libp2p/go-libp2p/p2p/transport/webtransport.(*stream).Reset(0xc00fcd23c0)
	/home/hugo/go/pkg/mod/github.com/libp2p/go-libp2p@v0.24.1/p2p/transport/webtransport/stream.go:54 +0x20
github.com/libp2p/go-libp2p/p2p/net/swarm.(*Stream).Reset(0xc02b010a00)
	/home/hugo/go/pkg/mod/github.com/libp2p/go-libp2p@v0.24.1/p2p/net/swarm/swarm_stream.go:86 +0x2a
github.com/libp2p/go-libp2p/p2p/host/basic.(*BasicHost).NewStream(0xc0008fc780, {0x2b5a0e0, 0xc01e869170}, {0xc00550a420, 0x26}, {0xc00037a860, 0x1, 0x0?})
	/home/hugo/go/pkg/mod/github.com/libp2p/go-libp2p@v0.24.1/p2p/host/basic/basic_host.go:636 +0x2bb
github.com/libp2p/go-libp2p-kad-dht/internal/net.(*peerMessageSender).prep(0xc01f123c20, {0x2b5a0e0?, 0xc01e869170?})
	/home/hugo/go/pkg/mod/github.com/libp2p/go-libp2p-kad-dht@v0.20.0/internal/net/message_manager.go:216 +0x6a
github.com/libp2p/go-libp2p-kad-dht/internal/net.(*peerMessageSender).SendRequest(0xc01f123c20, {0x2b5a0e0, 0xc01e869170}, 0xc01d88d830?)
	/home/hugo/go/pkg/mod/github.com/libp2p/go-libp2p-kad-dht@v0.20.0/internal/net/message_manager.go:277 +0x12c
github.com/libp2p/go-libp2p-kad-dht/internal/net.(*messageSenderImpl).SendRequest(0xc0014ea800, {0x2b5a038, 0xc01bc02ec0}, {0xc01d88d830, 0x26}, 0xc01eaef000?)
	/home/hugo/go/pkg/mod/github.com/libp2p/go-libp2p-kad-dht@v0.20.0/internal/net/message_manager.go:88 +0x374
github.com/libp2p/go-libp2p-kad-dht/pb.(*ProtocolMessenger).GetClosestPeers(0xc00037a930, {0x2b5a038, 0xc01bc02ec0}, {0xc01d88d830, 0x26}, {0xc01dfd4b70?, 0x0?})
	/home/hugo/go/pkg/mod/github.com/libp2p/go-libp2p-kad-dht@v0.20.0/pb/protocol_messenger.go:108 +0xd4
github.com/libp2p/go-libp2p-kad-dht.(*IpfsDHT).FindPeer.func1({0x2b5a038, 0xc01bc02ec0}, {0xc01d88d830, 0x26})
	/home/hugo/go/pkg/mod/github.com/libp2p/go-libp2p-kad-dht@v0.20.0/routing.go:604 +0xfb
github.com/libp2p/go-libp2p-kad-dht.(*query).queryPeer(0xc02b47bef0, {0x2b5a038, 0xc01bc02ec0}, 0xc000a03530?, {0xc01d88d830, 0x26})
	/home/hugo/go/pkg/mod/github.com/libp2p/go-libp2p-kad-dht@v0.20.0/query.go:408 +0x26e
created by github.com/libp2p/go-libp2p-kad-dht.(*query).spawnQuery
	/home/hugo/go/pkg/mod/github.com/libp2p/go-libp2p-kad-dht@v0.20.0/query.go:325 +0x44a

[marten-seemann]

Fixed by #1968.