Navigation stack not preserved when switching tabs

[ethanlee16]

Describe the bug: What happened?
This is probably low-priority, but a nice QoL thing to add if you have time: when navigating between tabs in the app, the "stack" or state of views in each tab is not preserved.

url or screen that error occurred?
Tab bar, all views

To Reproduce Bug

1. Navigate to an article from the Manuals tab.
2. Switch to the Favorites tab.
3. Switch back to the Manuals tab.
4. Observe that the Article you had open is no longer in-view.

Expected behavior?
I expect that each tab preserves its own view state when switching between them. See most tab-based apps on iOS: Phone, Contacts, Photos, Facebook, Twitter.

Environment (please complete the following information):
Which environment(s) is this bug located in?

• production

cc: @susan-lin