Playback 2023: Skip "Plus stories" in sequence

[ashiagr]

📘 Part of: #1463

This PR adds a mechanism to:

1. Set which stories are Plus or not;
2. Skip a bunch of Plus stories in sequence for a non-paid user
3. Skip a bunch of Plus stories in sequence for a non-paid user when going to previous stories

Basically — given the "Plus stories" will have an upsell, we don't want users to see the same story multiple times. So we just display it once, whether is going to next stories or previous one.

To test

Before testing, add override val plusOnly: Boolean = true in StoryYearOverYear and StoryCompletionRate.
Note that the first plus story "StoryYearOverYear" doesn't have an upsell yet.

Then:

1. Run the app
2. Login with Free account
3. Let the stories run (don't tap to skip to the next or to the previous one)
4. ✅ After the "YearOverYear" story is shown, it should skip to the last one
5. Tap to go to the previous story
6. ✅ It should go back to the "YearOverYear" (skipping CompletionRate story)
7. On the "YearOverYear" story, tap to go next
8. ✅ It should go to the last story
9. Exit the stories
10. Assign Plus plan to account
11. Tap "Refresh now" on Profile tab
12. Repeat the testing steps
13. ✅ However, all stories should show (no stories will be skipped)
14. Assign Patron plan to account
15. Tap "Refresh now" on Profile tab
16. Repeat the testing steps
17. ✅ All stories should show (no stories will be skipped)

** Tests cover skip scenarios when there are multiple plus stories in between

Checklist

• If this is a user-facing change, I have added an entry in CHANGELOG.md
• Ensure the linter passes (./gradlew spotlessApply to automatically apply formatting/linting)
• I have considered whether it makes sense to add tests for my changes
• All strings that need to be localized are in modules/services/localization/src/main/res/values/strings.xml
• Any jetpack compose components I added or changed are covered by compose previews

I have tested any UI changes...

• with different themes
• with a landscape orientation
• with the device set to have a large display and font size
• for accessibility with TalkBack

[mchowning]

This is working well. I imagine it was a bit tricky getting that logic just right. Thanks for adding the tests.