ZSort handling issue with composite's children

[mikz30]

• Issue : When a composite has more than a single level of children, the z sorting of grand-children and lower parts ignores the composite.
• How to reproduce it: A simple example can be a node tree like part A -> composite B -> node C -> part D, with part A and part D overlapping, where zB < zA and zA < zC + zD. Part A will cover part D, while on Inochi Creator part D is on top when zB < zA regardless of zC and zD. It will work as expected when part D is a direct child of composite B.
• Solution?: This might be addressed in PR Feature: Add Draw List and fix clippy warnings #108, but the pr doesn't seem to be clean enough for a single issue and it changed quite a lot other stuffs.