MINOR: quic: Remove call to qc_rm_hp_pkts() from I/O callback

MINOR: quic: Remove call to qc_rm_hp_pkts() from I/O callback

quic_conn_io_cb() is the I/O handler callback used during the handshakes.
quic_conn_app_io_cb() is used after the handshakes. Both call qc_rm_hp_pkts()
before parsing the RX packets ordered by their packet numbers calling qc_treat_rx_pkts().
qc_rm_hp_pkts() is there to remove the header protection to reveal the packet
numbers, then reorder the packets by their packet numbers.

qc_rm_hp_pkts() may be safely directly called by qc_treat_rx_pkts(), which is
itself called by the I/O handlers.