Fixes#2636
## Changes
- Displays trials scheduled for cancellation alongside non-trials
scheduled for cancellation
- Adds filter for "bad states" — active orgs that have a cancelled
subscription, orgs with a cancellation date in the past, and empty
subscription ids currently, but could be extended as necessary
- Displays scheduled-for-cancellation trials in the "trialing" filter as
well
- Improves display of future cancellation durations for both active
subscriptions and trials
- Surfaces issues where a trial cancellation was scheduled for the past
but the org is still active
- Swaps out `sl-tooltip`s for `btrix-popover`s in popovers with longer
details
- Adds correct heading levels, `tabindex`, and orientation for popovers
in use here
## Follow-ups
Once #2637 is merged we can ~~swap out the `sl-tooltip`s for
`btrix-popover`s here~~ _done!_ & in the superadmin stats card
7f44f43647