openssl-quic: ignore unexpected streams opened by server

openssl-quic: ignore unexpected streams opened by server

HTTP/3 defines "reserved stream types" that are intended to be ignored
by a receiver. This is part of the "greasing" effort that flexes parts
of the protocol that are needed for future extensions.

curl's OpenSSL-QUIC implementation treated all unexpected streams as
an error. Which seems the right thing to do *but* for these reserved types.
However OpenSSL does not expose this type and thus, curl needs to silently
discard all unexpected streams opened by the server to allow interop
with servers that flex the GREASE parts.

Fixes #18780
Reported-by: Pocs Norbert
Closes #18791