Core/Vehicles: always enable gravity after leaving an vehicle to make sure that switching between vehicles wont disable gravity forever

src/server/game/Entities/Vehicle/VehicleDefines.h

@@ -80,13 +80,11 @@ struct PassengerInfo
 {
     ObjectGuid Guid;
     bool IsUnselectable;
-    bool IsGravityDisabled;
 
     void Reset()
     {
         Guid.Clear();
         IsUnselectable = false;
-        IsGravityDisabled = false;
     }
 };