BUG/MINOR: quic: reject invalid max_udp_payload size

BUG/MINOR: quic: reject invalid max_udp_payload size

Add a checks on received max_udp_payload transport parameters. As
defined per RFC 9000, values below 1200 are invalid, and thus the
connection must be closed with TRANSPORT_PARAMETER_ERROR code.

Prior to this patch, an invalid value was silently ignored.

This should be backported up to 2.6. Note that is relies on previous
patch "MINOR: quic: extend return value on TP parsing".

(cherry picked from commit 4bc7aa548adcd9ee424c65cd346e94f8749dce64)
Signed-off-by: Willy Tarreau <w@1wt.eu>