game: remove duplicate initial-spells LOG_INFO and downgrade debug spell list

- world_packets.cpp::InitialSpellsParser::parse already logs spell count
  at LOG_INFO; remove the duplicate count from handleInitialSpells()
- Downgrade verbose format-detection LOG_INFO to LOG_DEBUG (packet size,
  format name, first-10 spell IDs) — these are diagnostic details that
  clutter INFO output without adding operational value

src/game/game_handler.cpp

@@ -12770,7 +12770,6 @@ void GameHandler::handleInitialSpells(network::Packet& packet) {
 
     knownSpells = {data.spellIds.begin(), data.spellIds.end()};
 
-    LOG_INFO("SMSG_INITIAL_SPELLS: ", knownSpells.size(), " spells");
     LOG_DEBUG("Initial spells include: 527=", knownSpells.count(527u),
               " 988=", knownSpells.count(988u), " 1180=", knownSpells.count(1180u));