Drop internal fork of h2

[bleggett]

Spun out of: https://github.com/istio/ztunnel/pull/998#pullrequestreview-2034609417

Before we can do this:

• https://github.com/hyperium/h2/pull/772 or equivalent has to merge in upstream.

[howardjohn]

PR merged so hopefully they tag a release. unfortunately you need a patch in cargo if not, unlike go

[bleggett]

woo, happy with the turnaround either way.