Deduplicate smallvec dependency

[ordian]

Currently we have several versions of the same (transitive) dependency, e.g.:

smallvec v0.2.1
smallvec v0.4.5
smallvec v0.6.5

It would be nice to remove duplicates, which in turn will reduce compile time and maybe binary size.
To see the list of dependencies, run: cargo tree --no-indent | sort | rg -v "\(\*\)$" | uniq

[debris]

I don't think we should have a generic issue for all duplicate dependencies in parity. It should be a policy to avoid them, but with so many of them, the duplication is sometimes inevitable

[ordian]

closed by #9657