fix(vec_init_then_push): don't lint pushes from a macro expansion

[JoakoI98]

Fixes #16131

A one-line check that will not count pushes from macro expansions. I'm using from_expansion so same-crate macros won't be counted
Also added UI tests to avoid regression

changelog: [vec_init_then_push]: don't lint when the push calls come from a macro expansion

[rustbot]

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