Add close button to site creation checkout

[irfano]

This adds a close button to the checkout page in the site creation flow. If the close button is tapped, the purchase will be canceled, and the site will be created.

Screen_recording_20231019_014356.mp4

To test:

1. Enable Plans in Site Creation feature flag
2. Select Site Picker
3. Create new WordPress.com site
4. Select a domain
5. Select a paid plan
6. Verify there is a close button at the top.
7. Tap the close button.
8. Verify the checkout page is closed, and the site preview page with the free domain is launched.
9. Repeat 2-5.
10. Tap the system back button.
11. Repeat 8.

Regression Notes

1. Potential unintended areas of impact
   None

2. What I did to test those areas of impact (or what existing automated tests I relied on)
   Nothing

3. What automated tests I added (or what prevented me from doing so)
   This is not a good case for an automated test.

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.

UI Changes testing checklist:

• Portrait and landscape orientations.
• Light and dark modes.
• Fonts: Larger, smaller and bold text.
• High contrast.
• Talkback.
• 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)
• Large and small screen sizes. (Tablet and smaller phones)
• Multi-tasking: Split screen and Pop-up view. (Android 10 or higher)

[wpmobilebot]

📲 You can test the changes from this Pull Request in WordPress by scanning the QR code below to install the corresponding build.

	App Name	WordPress
	Flavor	Jalapeno
	Build Type	Debug
	Version	pr19411-576c221
	Commit	576c221
	Direct Download	wordpress-prototype-build-pr19411-576c221.apk

Note: Google Login is not supported on these builds.

[wpmobilebot]

📲 You can test the changes from this Pull Request in Jetpack by scanning the QR code below to install the corresponding build.

	App Name	Jetpack
	Flavor	Jalapeno
	Build Type	Debug
	Version	pr19411-576c221
	Commit	576c221
	Direct Download	jetpack-prototype-build-pr19411-576c221.apk

Note: Google Login is not supported on these builds.

[ravishanker]

It should probably, display this free site confirmation step, instead of the paid plan confirmation

[ravishanker]

Actually, there's an exit flow already that can be used. It already asks if they want to exit, and lands back on site list.

Pushed a commit, not sure, which one would work best though

[irfano]

Actually, there's an exit flow already that can be used. It already asks if they want to exit, and lands back on site list.

The dialog on the progress screen mentions, "You may lose your progress," but when coming back from the checkout, the site has already been created. I believe that closing the checkout screen without displaying an additional dialog is currently a better approach. This is also consistent with how it is handled on iOS.

It should probably, display this free site confirmation step, instead of the paid plan confirmation

I have made the necessary changes to address this. Can you please review it again, @ravishanker?

[ravishanker]

LGTM 👍