fix(Core/PlayerTaxi): prevent pop_front crash (#22292)

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

src/server/game/Entities/Player/PlayerTaxi.h

@@ -65,6 +65,9 @@ public:
     [[nodiscard]] uint32 GetCurrentTaxiPath() const;
     uint32 NextTaxiDestination()
     {
+        if (m_TaxiDestinations.empty())
+            return 0;
+
         m_TaxiDestinations.pop_front();
         return GetTaxiDestination();
     }