TUN-10557: Bump quic-go v0.59.1

Bumps quic-go to v0.59.1 (chungthuang fork rebased from upstream v0.45 onto
v0.59.1). Upstream removed the `logging` package and replaced its
callback-based ConnectionTracer with the structured `qlog`/`qlogwriter` event
API, which required migrating cloudflared's QUIC metrics collection.

Migrations:

- quic/tracing.go: connTracer no longer fills a logging.ConnectionTracer
  callback struct. It implements qlogwriter.Trace + qlogwriter.Recorder and
  dispatches qlog events (PacketSent, PacketReceived, MetricsUpdated, ...) to
  the collector through RecordEvent. NewClientTracer now returns a function
  compatible with quic.Config.Tracer.

- quic/metrics.go: collector methods take qlog types (qlog.Frame,
  qlog.PacketType, qlog.MetricsUpdated, ...) and plain int64 in place of the
  removed logging.ByteCount/Frame/RTTStats/TransportParameters.

- quic/conversion.go: PacketType, PacketDropReason and PacketLossReason are
  strings upstream rather than numeric iotas, so the converters become
  pass-through allowlists. CongestionState is also a string;
  congestionStateToFloat maps it back to the numeric gauge values cloudflared
  exports.

- quic.Connection/quic.Stream became *quic.Conn/*quic.Stream; updated
  ConnWithCloser, SafeStreamCloser and the connection package accordingly.
  Tests and generated mocks (mocks/mock_quic_connection.go) were adapted to
  the new pointer-based API.

Closes TUN-10557

vendor/github.com/google/pprof/CONTRIBUTORS

@@ -1,16 +0,0 @@
-# People who have agreed to one of the CLAs and can contribute patches.
-# The AUTHORS file lists the copyright holders; this file
-# lists people.  For example, Google employees are listed here
-# but not in AUTHORS, because Google holds the copyright.
-#
-# https://developers.google.com/open-source/cla/individual
-# https://developers.google.com/open-source/cla/corporate
-#
-# Names should be added to this file as:
-#     Name <email address>
-Raul Silvera <rsilvera@google.com>
-Tipp Moseley <tipp@google.com>
-Hyoun Kyu Cho <netforce@google.com>
-Martin Spier <spiermar@gmail.com>
-Taco de Wolff <tacodewolff@gmail.com>
-Andrew Hunter <andrewhhunter@gmail.com>