outbound proxy protocol miss in various scenarios

With `proxy.config.http.proxy_protocol_out=2` enabled, we identified some cases when the proxy protocol packet is not send to the origin.

- when session is private on clear http origin connection , i created a small PR for quick fix purposes only (https://github.com/apache/trafficserver/pull/12336)

- when client use http/2 and origin is http/1.1, and multiple h2 streams are dispatched to origin

- when origin use tls

Tested on ATS 10.0.6