Enable the new landing screen in WordPress app

[ovitrif]

Closes #17870

This PR enables the new landing screen in the WordPress app. Testing was already done as part of the project implementation.

To be merged only after the release/21.7 branch is cut.

To test:

1. Verify CI checks pass.
2. Open WP and JP app
3. Verify The new landing screen is displayed when logged out

Regression Notes

1. Potential unintended areas of impact
   N/a

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

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

PR submission checklist:

• I have completed the Regression Notes.
• 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.

[wpmobilebot]

📲 You can test these changes on WordPress by downloading wordpress-installable-build-pr17871-3904eeb.apk

	💡 Scan this QR code with your Android phone to download and install the APK directly on it.
	App	WordPress
	Build Flavor	Jalapeno
	Build Type	Debug
	Commit	3904eeb

Note: This installable build uses the JalapenoDebug build flavor, and does not support Google Login.

[wpmobilebot]

📲 You can test these changes on Jetpack by downloading jetpack-installable-build-pr17871-a4a0968.apk

	💡 Scan this QR code with your Android phone to download and install the APK directly on it.
	App	Jetpack
	Build Flavor	Jalapeno
	Build Type	Debug
	Commit	a4a0968

Note: This installable build uses the JalapenoDebug build flavor, and does not support Google Login.

[antonis]

Thank you for tackling this @ovitrif 🙇
The code changes look good and the CI build I've tested on my Pixel 5/Android 13 showed the new landing screen as expected 🎉