chore: prune deps

[LesnyRumcajs]

Summary of changes

Some dependencies are no longer needed but weren't cleaned in the past. Sadly, the tooling I used to assert this is lacking;

• cargo udeps had lots of false negatives
• our ruby script had lots of false positives

With some back and forth with the compiler, I managed to prune the dependencies a bit. It compiles fine on Forest shashank/v15-builtin-actors.

Reference issue to close (if applicable)

Closes

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