For a few reasons
1. This step is really, really slow. I don't think there's sufficient
value in a slow CI step to keep it
2. Whenever we add an integration test it needs to be added to the
ignore list. I want to keep friction on adding such tests as low as
is possible.
3. We already run tests in a bunch of places, so I don't think this is
needed
Ref: #1123
This change saves us from needing to keep a copy of the checksum in atuin.nix, so that Cargo.lock can remain as the sole source of truth for the dependency versions.
