Remove an obsolete TODO from quic_framer.cc about changing the public packet header format for post v32 versions. This todo was adding in the fallout from the PAN drama. But I think it's not worth the risk of touching the header format again so let's just leave it alone and it'll be moot once v43 is removed. gfe-relnote: n/a - Remove an obsolete TODO from quic_framer.cc PiperOrigin-RevId: 276576983 Change-Id: Ia8ae360ea50c4257a0982651b2dcbff112802a43