Previously signed-in user's Contacts become visible to another user for a while

[weaponsforge]

Description

The previously signed-out user's contacts list becomes visible for a split-second when another user signs-in on the same browser tab, or another browser tab.

We should not display another user's Contacts list to other users. We should either:

• Clear all contacts cache on sign-out
• Find ways to not render a previously signed-out user's Contacts to newly signed-in users

Steps to Reproduce

1. Sign-in to https://weaponsforge.github.io/my-phonebook and create several Contacts.
2. Sign-out
3. Sign-in again to https://weaponsforge.github.io/my-phonebook using another account.
   • Take note, the first account's Contacts list flashes briefly in the newly signed-in user's /contacts page before getting replaced with the user's actual Contacts list

Please view the attached video of the bug for reference.

Video: Previously signed-in user's ([email protected]) Contacts list flashes briefly after another user ([email protected]) signs-in

cached-contacts.mp4