feat(s2n-quic-dc): update MTU on dc path when MTU is updated #4846

Job	Run time
env	3s
s2n-quic-qns (debug)	2m 22s
s2n-quic-qns (release)	7m 26s
h3spec (s2n-tls)	15s
h3spec (rustls)	19s
attack (udp)	5m 30s
bench	9m 31s
interop (aioquic, s2n-quic)	17m 22s
perf (s2n-quic, s2n-quic)	1m 17s
interop (chrome, s2n-quic)	5m 20s
perf (s2n-quic-null, s2n-quic-null)	50s
interop (go-x-net, s2n-quic)	11m 41s
interop (kwik, s2n-quic)	13m 34s
interop (lsquic, s2n-quic)	13m 6s
interop (msquic, s2n-quic)	16m 27s
interop (mvfst, s2n-quic)	11m 9s
interop (neqo, s2n-quic)	16m 41s
interop (ngtcp2, s2n-quic)	13m 53s
interop (picoquic, s2n-quic)	15m 39s
interop (quic-go, s2n-quic)	12m 53s
interop (quiche, s2n-quic)	16m 49s
interop (quinn, s2n-quic)	13m 49s
interop (s2n-quic, aioquic)	18m 6s
interop (s2n-quic, go-x-net)	11m 46s
interop (s2n-quic, haproxy)	12m 10s
interop (s2n-quic, kwik)	11m 58s
interop (s2n-quic, lsquic)	11m 12s
interop (s2n-quic, msquic)	12m 50s
interop (s2n-quic, mvfst)	9m 52s
interop (s2n-quic, neqo)	12m 50s
interop (s2n-quic, nginx)	10m 31s
interop (s2n-quic, ngtcp2)	12m 50s
interop (s2n-quic, picoquic)	12m 0s
interop (s2n-quic, quic-go)	10m 32s
interop (s2n-quic, quiche)	11m 37s
interop (s2n-quic, quinn)	11m 56s
interop (s2n-quic, s2n-quic)	12m 10s
interop (s2n-quic, s2n-quic-rustls)	12m 23s
interop (s2n-quic, xquic)	11m 44s
interop (s2n-quic-rustls, s2n-quic)	12m 9s
interop (xquic, s2n-quic)	15m 59s
perf-report	18s
interop-report	14s
	7h 21m 3s

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