Fix crash in Reader stream empty state views

[kean]

Fixes https://a8c.sentry.io/issues/6153580880:

Unable to activate constraint with anchors <NSLayoutYAxisAnchor:0x3038cdd00 "_TtGC11WordPressUI13UIHostingViewGVS_14EmptyStateViewGV7SwiftUI5LabelVS2_4TextVS2_5Image_GSqS4__VS2_9EmptyView__:0x109441680.top"> and <NSLayoutYAxisAnchor:0x30390d500 "WordPress.ReaderDiscoverHeaderView:0x1096cec00.bottom"> because they have no common ancestor.  Does the constraint or its anchors reference items in different view hierarchies?  That's illegal

I'm not sure when this happens, but I decided to keep it simple and lay it out with frames. It also fixes an issue with the bottom part of the view being not scrollable (only the header was).

I kept the nice parallax effect but, of course, you can drag from anywhere.

Simulator.Screen.Recording.-.iPhone.16.Pro.-.2024-12-18.at.13.17.10.mp4

To test:

You can easily test It by replacing this:

    override func predicateForFetchRequest() -> NSPredicate {
         return NSPredicate(format: "post != NULL OR topics.@count != 0 OR sites.@count != 0")
     }

with this:

    override func predicateForFetchRequest() -> NSPredicate {
         return NSPredicate(format: "post != NULL AND topics.@count == 999 AND sites.@count != 0")
     }

or just disabling internet connection

Regression Notes

1. Potential unintended areas of impact

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

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

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.

Testing checklist:

• WordPress.com sites and self-hosted Jetpack sites.
• Portrait and landscape orientations.
• Light and dark modes.
• Fonts: Larger, smaller and bold text.
• High contrast.
• VoiceOver.
• Languages with large words or with letters/accents not frequently used in English.
• Right-to-left languages. (Even if translation isn’t complete, formatting should still respect the right-to-left layout)
• iPhone and iPad.
• Multi-tasking: Split view and Slide over. (iPad)

[dangermattic]

	1 Warning
⚠️	This PR is assigned to the milestone 25.6 ❄️. The due date for this milestone has already passed. Please assign it to a milestone with a later deadline or check whether the release for this milestone has already been finished.

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📲 You can test the changes from this Pull Request in Jetpack Alpha by scanning the QR code below to install the corresponding build.

	App Name	Jetpack Alpha
	Configuration	Release-Alpha
	Build Number	pr23908-4b8532f
	Version	25.6
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[crazytonyli]

The interaction is neat!

[crazytonyli]

It probably doesn't make much difference in reality, but I think it only make sense to use bounds here, because headerView.frame is not in headerView's coordinate space?

Suggested change

	return headerView.convert(headerView.frame, to: view).maxY
	return headerView.convert(headerView.bounds, to: view).maxY

[kean]

Good catch. I wrote it hastily, and what it currently doesn't make a whole lot of space. It should be:

return tableView.convert(headerView.frame, to: view).maxY

Convert the header view frame from the table view coordinate space (its superview) to the coordinate space of the main view.

I updated it.