Clean up extra dependencies added by zbus

Zbus was added as part of https://github.com/bottlerocket-os/bottlerocket-core-kit/pull/661 is merged, which brought a new set of dependencies that are newer than those in the current first party sources, specifically:

- nix
- rand
- rand_chacha
- rand_core
- winnow

I tried to update `nix` but it requires some refactor in `apiserver`, `apiclient` and `thar-be-updates`. I have not tried with all the others.

Review pull request 661 and the current first-party dependency sources to see how zbus introduced nix, rand, rand_chacha, rand_core, and winnow. Then inspect the dependency usage in apiserver, apiclient, and thar-be-updates, starting with nix since the issue notes required refactoring there. Done means the redundant newer dependencies are cleaned up without breaking these components.

Written by the indexing model from the issue text.