Issue/9157 site creation back pressed

[malinajirka]

Fixes #9157

Note: This PR should be reviewed after #9142 is merged.

A warning dialog is shown when the user presses the back button while the site creation is already in progress - the flow is exited when they press the positive dialog button.
The flow is exited right away when they press the back button after the site preview was shown.

@SylvesterWilmott I haven't modified the style of the warning dialog to keep it consistent with the rest of the app. Is it ok? Btw has the text been reviewed?

To test:

1. My Site
2. Switch Site
3. Plus sign icon in the top right corner
4. Create a WordPress.com site
5. Make sure the back button works on Segments, Verticals, SiteInfo and Domains screen
6. Go to the domain screen
7. Enter a domain name
8. Click on the "Create Site" button
9. Press the back button while the fullscreen dialog is shown
10. Warning dialog is shown - make sure it survives rotation
11. Click on "Exit"
12. Make sure the flow is dismissed

---

1. My Site
2. Switch Site
3. Plus sign icon in the top right corner
4. Create a WordPress.com site
5. Select a segment
6. Skip
7. Skip
8. Enter a domain name
9. Click on the "Create Site" button
10. Wait until the site preview is shown
11. Click on the back button and make sure it's suppressed Click on the back button and make sure the flow is exited

Update release notes:

• [ x ] If there are user facing changes, I have added an item to RELEASE-NOTES.txt.

[SylvesterWilmott]

@malinajirka Thanks, looks good. The text wasn't reviewed, lets add Needs copy review tag.

[kristastevens]

How about if we simplified the copy, just slightly:

You may lose your progress. Are you sure you want to exit?
[CANCEL EXIT]

[malinajirka]

Thanks! The text updated in 8768cce

[oguzkocer]

@malinajirka I couldn't review this PR today due to the conflicts (the changeset looks weird right now). I thought about updating the PR myself, but I am not 100% sure if I can actually finish it on time anyway since I am afk for tomorrow.

Could we do one of the following for this:

1. Postpone it to 11.9
2. Get someone else to review this tomorrow. It'd probably have to be someone in EU so you can address the possible issues immediately.

Really sorry about this. My unexpected afk yesterday messed up the timeline a little bit :(

cc @kwonye if you can help in any way.

[malinajirka]

@oguzkocer Don't worry about it, there is no reason to apologize;). I should have created the PR sooner.

@kwonye If you had time and didn't mind reviewing it, it'd be great. I can address any feedback in the evening. But don't worry about it too much.

[loremattei]

Hey! I'm moving this one to 11.9 since 11.8 has been cut. If it has to land 11.8, please feel free to move it back, target the release branch and ping me to build a new beta.

[oguzkocer]

@malinajirka I am done with my first pass. I have raised a few questions for you, but none of it is actually a blocker. Let me know what you think!

[malinajirka]

Thanks @oguzkocer for the review;)! I've fixed all the issues. It's ready for another round.

[oguzkocer]

@malinajirka The second testing instructions state that the back button should be suppressed if the site preview is shown. I tested this and it's not suppressed. Is that really the behavior we want? I don't think we are suppressing it right now in the code.

[malinajirka]

@oguzkocer The instruction was outdated, sorry my bad:(.

[oguzkocer]

The instruction was outdated, sorry my bad:(.

No worries, just wanted to double check. I reviewed the changes and tested the rest yesterday, so