Unified Login: Step 1 - fix merge conficts and get a working build

[AmandaRiu]

Closes #2655. This PR merges in the latest unified login changes from the WordPressLoginFlow library which included fixing merge conflicts and doing the minimum amount of work required to get a successful build. This was done to keep the PR review process as manageable as possible.

Note that while this branch should build successfully, login is broken. Login will be fixed in later PRs.

To Test

Pull down this branch and verify it builds.

Update release notes:

• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

[peril-woocommerce]

	Fails
🚫	Danger failed to run /app/danger-0.9go5jor9ifd.ts.
🚫	Danger failed to run /app/danger-0.7fenpwjfdi7.ts.

	Warnings
⚠️	PR has more than 500 lines of code changing. Consider splitting into smaller PRs if possible.

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 woocommerce-android git checkout issue/2655-unified-login-1 git subtree push --prefix=libs/login/ https://github.com/wordpress-mobile/WordPress-Login-Flow-Android.git merge/woocommerce-android/2722 Browse to https://github.com/wordpress-mobile/WordPress-Login-Flow-Android/pull/new/merge/woocommerce-android/2722 and open a new PR.

Error TypeError

Cannot read property 'added' of null
TypeError: Cannot read property 'added' of null
    at Object.exports.default (/app/danger-0.9go5jor9ifd.ts:16:44)
    at process._tickCallback (internal/process/next_tick.js:68:7)

Dangerfile

11|         warn("The PlayStoreStrings.po file must be updated any time changes are made to release notes");
12|     }
13| 
14|     // If changes were made to the strings, make sure they follow our guidelines
15|     const modifiedStrings = modifiedFiles.filter((path: string) => path.endsWith('values/strings.xml'))
----------------------------------------------^
16| 
17|     for (let file of modifiedStrings) {        
18|         const stringDiffs = await danger.git.diffForFile(file)
19| 

Error TypeError

Cannot read property 'diff' of null
TypeError: Cannot read property 'diff' of null
    at checkCommitDiffs (/app/danger-0.7fenpwjfdi7.ts:43:49)
    at process._tickCallback (internal/process/next_tick.js:68:7)

Dangerfile

38|         if (git === undefined) {
39|             console.log("About to crash due to an error")
40|             console.log("File:", thisFile)
41|             console.log("Danger Object: ", danger)
42| 
---------------------------------------------------^
43|             if (danger !== undefined) {
44|                 console.log("Danger is no longer defined")
45|             }
46|             else {

Generated by 🚫 dangerJS

[peril-woocommerce]

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

[anitaa1990]

App builds as expected