Issue/9854 site creation loading

[malinajirka]

Fixes #9854

Goal of this PR was to improve the look of the "creating site" loading screen.

Before	After

Dark

To test - test it on different screen sizes.

1. My Site
2. Click on the plus icon in the toolbar
3. Create WordPress.com site
4. Select a segment
5. Type something into the input
6. Select a domain - make sure to select a domain regular users won't ever need because it won't be available anymore after the site is created (eg. something like ehfiou4hto8743wyta8owyt3o8awyt87.wordpress.com)
7. Click on "Create site"
8. Notice the new loading screen - the text should be fade out and a new text should fade in every 2 seconds
9. Verify the loading screen is shown and the site gets created

---

1. My Site
2. Click on the plus icon in the toolbar
3. Create WordPress.com site
4. Select a segment
5. Type something into the input
6. Select a domain - make sure to select a domain regular users won't ever need because it will never be available again after the site is created (eg. something like asdfghjklqwertyuiop.wordpress.com)
7. Turn on airplane mode
8. Click on "Create site"
9. Notice an error screen is shown
10. Turn off the airplane mode
11. Click on retry
12. Verify the loading screen is shown and the site gets created

---

Anything else you can think of. This flow is vital, so should be tested with care.

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]

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

[peril-wordpress-mobile]

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

[oguzkocer]

Hi there! I will be freezing 14.6 in a little bit, to this PR is being bumped to 14.7. If you need this to be shipped in 14.6, please update the base branch to release/14.6 and give me a heads up when the PR is merged so I can release a new beta.

[jd-alexander]

Hi @malinajirka this works beautifully! Thank you for these amazing tests! They work really well and I learnt a lot about the coroutine APIs 😉
I left some minor comments. Once those are addressed I will do a second pass to ensure that this is tested thoroughly 🙇

[malinajirka]

Thank you @jd-alexander for the review !!! ;)

I've replied to your comments and simplified the code as you suggested.

I also realized the drawable doesn't look as it's supposed to in the dark mode. I pinged Klym and asked him about the best approach for solving the issue. I'm adding "do not merge" tag and it might make sense to do another round of the review when I fix the issue so you can quickly test even the dark mode. Thanks!

[malinajirka]

I've added the dark mode version of the drawable and this is now ready for test - ff51082

[jd-alexander]

Thanks @malinajirka The dark mode changes are great! Tested on both phone & tablet! All is looking well now 👍

[mbshakti]

Looks fantastic. Thanks @malinajirka!