Refactor QuicDispatcher tests The dispatcher tests were incorrectly using QUIC_CRYPTO CHLOs with TLS versions. This CL updates them to use real packets from GetFirstFlightOfPackets(). gfe-relnote: n/a, test-only PiperOrigin-RevId: 307802112 Change-Id: I0c5af0a273f74036da72587da3838a489064acaf