Scripts/ICC: Fix teleporter not removing players from Gunship

A more generic solution might be better, maybe depending on spell flags

Ref #25652

(cherry picked from commit 0ad1854d1c)

src/server/scripts/Northrend/IcecrownCitadel/go_icecrown_citadel_teleport.cpp

@@ -26,6 +26,7 @@
 #include "Spell.h"
 #include "SpellInfo.h"
 #include "SpellMgr.h"
+#include "Transport.h"
 
 static std::vector<uint32> const TeleportSpells =
 {
@@ -69,6 +70,11 @@ class icecrown_citadel_teleport : public GameObjectScript
                     return true;
                 }
 
+                // If the player is on the ship, Unit::NearTeleport() will try to keep the player on the ship, causing issues.
+                // For that we simply always remove the player from the ship.
+                if (Transport* transport = player->GetTransport())
+                    transport->RemovePassenger(player);
+
                 player->CastSpell(player, spell->Id, true);
                 return true;
             }