Core/Players: Check if player can enter the instance during login before trying to add him to map

* Fixes name displaying as "Unknown"

(cherry picked from commit 45994a177c128dc83ea01b0697377f7b74b5c4ba)
(cherry picked from commit c7bad70e55)

Conflicts:
	src/server/game/Entities/Player/Player.cpp
	src/server/game/Entities/Player/Player.h

src/server/game/Handlers/CharacterHandler.cpp

@@ -969,7 +969,7 @@ void WorldSession::HandlePlayerLogin(LoginQueryHolder* holder)
         }
     }
 
-    if (!pCurrChar->GetMap()->AddPlayerToMap(pCurrChar) || !pCurrChar->CheckInstanceLoginValid())
+    if (!pCurrChar->GetMap()->AddPlayerToMap(pCurrChar))
     {
         AreaTriggerStruct const* at = sObjectMgr->GetGoBackTrigger(pCurrChar->GetMapId());
         if (at)