Move User Lists to its own Page

What does this MR do?

Now that user lists are no longer listed on the feature flags page, we should link to the table of user lists instead of linking to the create a new user list page.

Part of moving the user lists table to its own page. There's no reason to have the user list's state embeded within feature flags anymore.

The table of user lists will be moving to its own page, so the first step is to clean up some of the feature flag table. Here, we remove the tab showing the user lists, as well as the component's ability to be in a tab.

For #322425 (closed)

Screenshots (strongly suggested)

480_Screen_Recording_2021-05-20_at_16.49.46

Does this MR meet the acceptance criteria?

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