Correction of an error that occurs in the log when combining vendor and trainer for TrinityCore

trinitycore_vendor_with_trainer.patch

From d2e54dc3e1970d1b1e7a25f13aabbbfcec712973 Mon Sep 17 00:00:00 2001
From: Haeniken <me@haeniken.com>
Date: Sun, 10 Oct 2021 14:13:39 +0300
Subject: [PATCH] fix

---
 src/server/game/Entities/Player/Player.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/server/game/Entities/Player/Player.cpp b/src/server/game/Entities/Player/Player.cpp
index 7fcef2250f..506e729c94 100644
--- a/src/server/game/Entities/Player/Player.cpp
+++ b/src/server/game/Entities/Player/Player.cpp
@@ -14367,12 +14367,14 @@ void Player::PrepareGossipMenu(WorldObject* source, uint32 menuId /*= 0*/, bool
                 case GOSSIP_OPTION_TRAINER:
                 {
                     Trainer::Trainer const* trainer = sObjectMgr->GetTrainer(creature->GetEntry());
-                    if (!trainer || !trainer->IsTrainerValidForPlayer(this))
+                    if (!trainer) // || !trainer->IsTrainerValidForPlayer(this))
                     {
                         TC_LOG_ERROR("sql.sql", "GOSSIP_OPTION_TRAINER:: Player %s %s requested wrong gossip menu: %u at Creature: %s (Entry: %u)",
                             GetName().c_str(), GetGUID().ToString().c_str(), menu->GetGossipMenu().GetMenuId(), creature->GetName().c_str(), creature->GetEntry());
                         canTalk = false;
                     }
+		    if (!trainer->IsTrainerValidForPlayer(this))
+			    canTalk = false;
 		    [[fallthrough]];
                 }
                 case GOSSIP_OPTION_GOSSIP:
-- 
2.20.1

Known bugs:
If an npc has a flag 16 without a training sheet, the server crashes.
This seems breaks the "multivendor" by Rochet2.