Support WordPress.com magic link login

[crazytonyli]

Fixes #24171.

This PR implements the option 1 in issue #24171.

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 25.9. 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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[wpmobilebot]

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	App Name	WordPress Alpha
	Configuration	Release-Alpha
	Build Number	pr24260-04cd083
	Version	25.8
	Bundle ID	org.wordpress.alpha
	Commit	04cd083
	App Center Build	WPiOS - One-Offs #11775

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[wpmobilebot]

📲 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	pr24260-04cd083
	Version	25.8
	Bundle ID	com.jetpack.alpha
	Commit	04cd083
	App Center Build	jetpack-installable-builds #10801

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[pmusolino]

Hey Tony, thanks for working on this issue, because I encountered the same issue few days ago.

While testing this PR, I encountered a blocking issue. If you follow these steps, you will not be able to log in with the magic link:

1. I created a new account in the app and logged in automatically.
2. I logged out (also in the webview).
3. I attempted to log in again.
4. I reached the view where I was asked to receive the magic link and pressed the button to receive the email.
5. I received the email and copy-pasted the link into Safari within the simulator.
6. I logged into the webview, then I was redirected to the app using the deeplink.
7. I got stuck on the previous view that asked me to check my email, and after closing it, I remained unauthenticated.

[crazytonyli]

@pmusolino Good catch! That bug slipped through after a code refactor. I have fixed the issue and have added an unit test to cover logging in via login links.

[pmusolino]

Thank you Tony, now it works as expected!

I just found an additional issue. Since you have more knowledge than me in login, I'm not sure it's strictly related to this PR, and it's probably how the magic link is handled on the web. Basically, if I'm already logged in on the browser (Safari), the magic link doesn't work and does not redirect me to the app, making it impossible to log in properly in the app. Wdyt?

[kean]

It worked but not exactly the way I would've expect. Some of these issues are web-specific and might be worth reporting and fixing before shipping it.

1. The "Authorize your account" screen was shown in a browser – I'd probably expect it to be shown in the app (ideally not at all).
2. The screen says "WordPress for iOS". I was logging it from "Jetpack".
3. I was logged out in the browser and for some reason it logged me in – that was not my intention.

4. No email auto-completion on the following screen: