Unified Login & Sign-Up: Create Sign-Up From Login functionality for Email + Magic Link method

[renanferrari]

Part of #11705

To test

Full Flow

0. Clear app data.
1. On the Prologue Screen, tap Log In.
2. If the Smart Lock dialog appears, dismiss it.
3. On the Email Screen, enter an email address that is not associated with a WordPress.com account.
4. Tap Next.
5. Notice the Sign-Up Magic Link screen.
6. Check email inbox of address used in Step 3.
7. Notice signup email from WordPress.com.
8. Complete the sign-up flow normally.

Jetpack Flow

0. Log in with a self-hosted site that is not associated with a WordPress.com account.
1. Go to My Site tab and tap Stats (or go to Notifications tab).
2. Tap the Install Jetpack button.
3. If the Smart Lock dialog appears, dismiss it.
4. On the Email Screen, notice there's no Don't have an account? Sign up button.
5. Enter an email address that is not associated with a WordPress.com account.
6. Tap Next.
7. Notice the Sign-Up Magic Link screen.
8. Check email inbox of address used in Step 3.
9. Notice signup email from WordPress.com.
10. Complete the sign-up flow normally.

Notes

• This doesn't add the Sign-Up From Login functionality for the Google Sign-In method just yet. This will be done in the following PR.
• This also doesn't remove the Sign-Up button from the Prologue screen. This will be addressed in a future task.
• Lastly, this also doesn't change the current labels used by the flows, so it may not always make sense.
• This PR make changes to the LoginFlow library. These changes will probably need to be merged to the LoginFlow library once our feature branch gets merged back to develop.

---

PR submission checklist:

• I have considered adding unit tests where possible.
• 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.

[peril-wordpress-mobile]

Messages

📖

This PR contains changes in the subtree libs/login/. It is your responsibility to ensure these changes are merged back into wordpress-mobile/WordPress-Login-Flow-Android. Follow these handy steps! WARNING: Make sure your git version is 2.19.x or lower - there is currently a bug in later versions that will corrupt the subtree history! cd WordPress-Android git checkout issue/11705-magic-link git subtree push --prefix=libs/login/ https://github.com/wordpress-mobile/WordPress-Login-Flow-Android.git merge/WordPress-Android/11708 Browse to https://github.com/wordpress-mobile/WordPress-Login-Flow-Android/pull/new/merge/WordPress-Android/11708 and open a new PR.

Generated by 🚫 dangerJS

[peril-wordpress-mobile]

You can trigger optional UI/connected tests for these changes by visiting CircleCI here.

[peril-wordpress-mobile]

You can test the changes on this Pull Request by downloading the APK here.

[planarvoid]

It looks really good 👍. I was able to test the first flow and it works well. I couldn't get a self-hosted site to test the Jetpack signup because the site generator doesn't work. I'll merge the PR after I test it.

[planarvoid]

I was able to test the flow with a self-hosted site and it works well 👍