[6.x] A deleted item remains in the sidebar

[ebeauchamps]

Bug description

I created a taxonomy, edited it to create a few terms, then deleted this taxonomy
The deleted taxonomy is still displayed in the sidebar
Clicking on its link in the sidebar generates a 404 and right after this the taxonomy isn't displayed anymore

similar to #12627

Screenshot right before deleting the taxonomy:

I delete the taxonomy here:

Screenshot after deleting it:

Clicking on the link:

How to reproduce

Create a taxonomy, create terms, delete the taxonomy

Logs

Environment

Environment
Application Name: StatamicFrenchTest
Laravel Version: 12.31.1
PHP Version: 8.4.13
Composer Version: 2.8.11
Environment: local
Debug Mode: ENABLED
URL: statamic6.test
Maintenance Mode: OFF
Timezone: UTC
Locale: en

Cache
Config: NOT CACHED
Events: NOT CACHED
Routes: NOT CACHED
Views: CACHED

Drivers
Broadcasting: log
Cache: file
Database: sqlite
Logs: stack / single
Mail: log
Queue: sync
Session: file

Storage
public/storage: NOT LINKED

Statamic
Addons: 0
Sites: 1
Stache Watcher: Enabled (auto)
Static Caching: Disabled
Version: 6.0.0-alpha.9 PRO

Installation

Fresh statamic/statamic site via CLI

Additional details

No response

[ebeauchamps]

ah, found something interesting:
When you delete the taxonomy from within the Terms page, the taxonomy is immediately deleted from the sidebar after your confirmation

[duncanmcclean]

Fixed by #12942