MINOR: qpack: report error on enc/dec stream close

MINOR: qpack: report error on enc/dec stream close

As specified by RFC 9204, encoder and decoder streams must not be
closed. If the peer behaves incorrectly and closes one of them, emit a
H3_CLOSED_CRITICAL_STREAM connection error.

To implement this, QPACK stream decoding API has been slightly adjusted.
Firstly, fin parameter is passed to notify about FIN STREAM bit.
Secondly, qcs instance is passed via unused void* context. This allows
to use qcc_emit_cc_app() function to report a CONNECTION_CLOSE error.