Fix QUIC issues

[EmelyanenkoK]

No description provided.

[github-actions]

1. quic/quic-sender.cpp:109-116 — DEFAULT_STREAM_SIZE_LIMIT is computed but never enforced when options_.max_size is unset because the guard still checks options_.max_size.has_value(). This leaves streams unbounded by default (potential memory/DoS risk). If the default is intended, drop the has_value() guard or set options_.max_size to the default at configuration time.

2. validator/impl/liteserver-cache.hpp:81-88 — The duplicate sendMessage guard is now an LRU cache. Under high churn, entries can be evicted while the original message is still in flight, allowing duplicates to be accepted again. If duplicate suppression needs to hold until completion (or at least for the 60s window), consider “touching” on duplicates and/or using an explicit TTL/in-flight tracking rather than LRU eviction.