Comment 7 for bug 1843376

To deal with lifetimes of CAAS objects, commit 36b4353d50430c8ca31b7a66d8a853e6db5cc5cc introduced killing the Leadership Tracker if the Uniter dies. However, it does so with a Worker.Kill() which kills the worker with no error, which the DependencyEngine then treats as "don't restart because I'm done". But the Uniter has a dependency on it, so the Uniter is unable to be restarted.

We should decouple restarting the workers.

If we just removed the catacomb.Init here:
https://github.com/juju/juju/blob/4530b4ddf5be45df371438fb7f20ef12b80a7d67/worker/uniter/uniter.go#L207

Then it would regress this PR:
https://github.com/juju/juju/pull/10087

Where unit '3' of a CAAS application might go away, but wouldn't stop the Leadership Tracker, which meant unit 4 couldn't become a leader. This doesn't happen in IAAS because we run a separate agent, and that agent dies when the unit is removed (vs in CAAS where we run all unit agents as a dependency from the application).