Improve UI: Show associated preferences to a tempted removed device

https://gitlab.cern.ch/push-notifications/notifications-design/-/issues/48

Final decision:

• No preferences associated
• Preferences associated, but all of the preferences have other devices also associated, and won't be left hanging
• At least one preference had only that device associated

For the 1st just delete, no modal 2nd, I would show the preferences list, but not block the delete action 3rd I would show a preference list and block until the preference that would be left with no devices is fixed.

https://mattermost.web.cern.ch/it-dep/pl/xomxswbw1brbprgg7azfi5np9w