small speedup and safety in operations with VehicleSeatEntry. testing.
Revert " try use atomic operations in LinkedList && Reference (must use less CPU then before). may have _ANY_ result, use with caution! thx Boxa for code"

This reverts commit 0ff97d2884cb2d99b016617ec4e03d8d5ca5efd2.
Always cleanup GroupGuid/OriginalGroupGuid while set new group. possible fix bug-using problems, identified after 3023. testing.