Add scan QR code optional CTA to LoginMagicLinkSentImprovedFragment

[JorgeMucientes]

Description

Adds new CTA to scan QR code from magic link sent screen. The goal was to add the least possible changes in the auth lib to ensure that backwards compatibility is not broken in case any other apps are using this screen.

Most of the changes are done in this PR inside WooCommerce Android repository. Nothing to test in this PR.

EDIT

After @hichamboushaba suggestion I removed LoginMagicLinkSentImprovedFragment from this library and migrated it to WooCommerce Android repo. So this PR just does that -> remove LoginMagicLinkSentImprovedFragment

Screenshots

[hichamboushaba]

@JorgeMucientes A suggestion, since we are planning on making more changes to this screen, why not just move it completely to Woo? I suggested this to @0nko before, and we decided to skip it because the work was already done, but now I see we are doing more changes, then maybe it's simpler to copy the code of the improved magic link screen and drop it in Woo, then we can get rid of the inheritance which makes code harder to reason about.

[JorgeMucientes]

Makes sense @hichamboushaba. We are sure WordPress is not using this right? I'll get to it!

[hichamboushaba]

We are sure WordPress is not using this right?

I looked at the WPAndroid repo now, and I confirm it's not used anywhere.

[JorgeMucientes]

Ready for review @hichamboushaba @0nko 🙏🏼