quic: convert openStream to Promise

Although most of the time openStream will be able to create the stream
immediately, when a stream is opened before the handshake is complete
we have to wait for the handshake to be complete before continuing.

PR-URL: https://github.com/nodejs/node/pull/34351


Reviewed-By: Robert Nagy <ronagy@icloud.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>