[hakari] use final-excludes rather than traversal-excludes

[sunshowers]

While looking at build performance I realized that we weren't unifying feature sets across rust-analyzer builds and ones done on the command line. Switching from traversal-excludes (i.e. omitted while computing the set of features for each package) to final-excludes (removed at the very end) addresses this issue.

This doesn't completely unify all feature sets (e.g. we have a few testing features within the workspace that can't be unified), but it does ensure that third-party dependencies are shared across all builds.

With this change, after running a cargo check within rust-analyzer:

% cargo check --all-targets
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.91s