Refactor permission checks to load ancestor permissions into memory
for all checks to make the different logics more explicit.

This PR deletes the old `ui` and `storybook` crates in favor of their
newer variants that we'll be landing to `main` in the near future.

### Motivation

These crates are based off the old version of GPUI 2 (the `gpui2`
crate).

At this point we have since transitioned to the new version of GPUI 2
(the `gpui3` crate, currently still on the `gpui2` branch).

Having both copies around is confusing, so the old ones are going the
way of the dinosaurs.

Release Notes:

- N/A

In addition to fixing a panic, this makes it slightly more convenient to
re-open disconnected channel notes views. I didn't make it automatic,
but it will at least replace the previous, disconnected view.

Release Notes:

- Fixed a crash that sometimes occurred when following someone with a
disconnected channel notes view open.