Blogging Prompts List: add the ability to show empty views for different scenarios.

[ScoutHarris]

Ref: #18502

This adds the ability to show empty views for different scenarios.

• No results
• No connection
• Loading prompts
• Loading error

Since the view is not fetching prompts yet, some hacking in BloggingPromptsViewController is required to get each empty view to show, which is noted below. The logic to toggle these states appropriately will be added later.

For the uninitiated 😄 , the NoResultsViewController provides this magic:

• If there is no connection, it detects it and creates the no connection view regardless of what it was configured with.
• In compact height, the image is automatically hidden.

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To test:

• Enable bloggingPrompts feature flag.
• Make the changes below for each empty view type.
• Go to Home tab > prompt card > View more prompts.
• Verify each view appears as shown below.

View hacking:

• No results view:
  • Set promptCount = 0.
• No connection view:
  • Set promptCount = 0.
  • Disconnect internet connection.
• Loading view:
  • Set isLoading = true.
• Error view:
  • In viewDidLoad, replace showNoResultsViewIfNeeded with showErrorView.

---

No Results	No Connection

Loading	Loading Error

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Regression Notes

1. Potential unintended areas of impact
   N/A

2. What I did to test those areas of impact (or what existing automated tests I relied on)
   N/A

3. What automated tests I added (or what prevented me from doing so)
   N/A

PR submission checklist:

• I have completed the Regression Notes.
• I have considered adding unit tests for my changes.
• I have considered adding accessibility improvements for my changes.
• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

[wpmobilebot]

You can test the changes in Jetpack from this Pull Request by:

• Clicking here or scanning the QR code below to access App Center
• Then installing the build number pr18515-be554f9 on your iPhone

If you need access to App Center, please ask a maintainer to add you.

[wpmobilebot]

You can test the changes in WordPress from this Pull Request by:

• Clicking here or scanning the QR code below to access App Center
• Then installing the build number pr18515-be554f9 on your iPhone

If you need access to App Center, please ask a maintainer to add you.

[wargcm]

Code looks good! I found a couple minor UI issues which probably don't need to be addressed in this PR:

1. There's some display issues for the no connection text in landscape mode when using large accessibility text. This is probably an existing issue with the no results view.
   

2. There's a small flicker when changing tabs. I compared it to the followers page for reference.

flicker.mp4

[ScoutHarris]

There's some display issues for the no connection text in landscape mode when using large accessibility text. This is probably an existing issue with the no results view.

Indeed it is. I'll not address that here.

There's a small flicker when changing tabs.

This will be fixed when the logic is added to properly display the views. Right now it's just always readding the empty view so it appears for all the tabs, which causes the flickering. In the future, it will depend on the loading status, tab contents, and whether it's already being displayed. i.e. I'll fix it later! 😄