Domain registration edge case: background user interactions while registration service is in progress

[jaclync]

(Followup issue from #11613)

Expected behavior

(Not expected, just my suggestion) user cannot navigate away while registration is still in progress with spinner shown, otherwise UI navigation on registration completion might not work as expected.

Actual behavior

Currently, user can tap on "< Back" and "Help" in navigation bar while registration is in running (shown in screenshot). In the two cases that trigger domain registration flow (Domain Credit and Automated Transfer flow with Business accounts), the behavior might be different on registration completion depending on whether user stays on the registration screen.

Steps to reproduce the behavior

• Prerequisites:
  • Domain credit flow: have a blog with any paid WordPress.com plan (e.g. Blogger plan) and its domain credit still available
  • Automated Transfer flow: have a blog with Business plan and its domain credit still available
• Enter a domain registration flow from Domain Credit or Automated Transfer flow with Business accounts
• Pick a *.blog domain (.blog has high purchase volume so that cancellation rate from testing has less effect on production domain service)
• Note that the same domain cannot be purchased by the same user after cancellation, so make sure this testing domain is not what you might want to own with the WP.com account :)
• Fill out registration details (these will be saved for the next time)
• Submit domain registration, and run the next step right away
• In navigation bar, tap "< Back" quickly and dismiss the domain registration modal, or tap "Help" to bring up another modal
• [Important] If this domain purchase is only for testing, make sure to cancel domain purchase shortly after testing on web in Account Profile --> Manage Purchases (official FAQ)

Tested on [device], iOS [version], WPiOS [version]

iOS 12.2 simulator

[jaclync]

A temporary workaround was added in 181bb68 that disables background user interactions while progress HUD is shown

[stale]

This issue has been marked as stale because:

• It has been inactive for the past year.
• It isn't in a project or a milestone.
• It hasn’t been labeled [Pri] Blocker, [Pri] High, or good first issue.

Please comment with an update if you believe this issue is still valid or if it can be closed. This issue will also be reviewed for validity and priority (cc @designsimply).