Make QHttp2ProtocolHandler discard all informational (1xx) replies with
the exception of 101.
According to RFC 9110:
"A client MUST be able to parse one or more 1xx responses received
prior to a final response, even if the client does not expect one.
A user agent MAY ignore unexpected 1xx responses."
Fixes: QTBUG-121755
Change-Id: I8b8d578f23d4fbe28929f8c54b3607bcaf85405f
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Juha Vuolle <juha.vuolle@qt.io>
6d08db8666