Add e2e coverage for additional scopes requests

#1566 introduced a more incremental way to request write scopes only when necessary. At the moment this is only used by Analytics, but shortly will be used by Tag Manager as well (#1608), and potentially further modules in the future.

While this has been tested and will be shipped without e2e tests in 1.9.0 (due to time constraints), we should have some e2e tests to cover these cases, since it’s not something that can reasonably be covered with Jest.

---

Do not alter or remove anything below. The following sections will be managed by moderators only.

Acceptance criteria

• There should be new e2e tests for the following:
  • Creating an Analytics account (via proxy & provisioning API) when not having the https://www.googleapis.com/auth/analytics.provision scope yet. Expected experience:
    • The user sees a notice above the button that explains they will need to grant additional permissions.
    • Upon clicking the button, they’re redirected to OAuth (should be mocked).
    • When returning, their original action is automatically invoked, without requiring them to click the button again.
    • They should be redirected to the Analytics TOS (can be mocked to an immediate success redirect to Site Kit (...?gatoscallback=1...)).
    • They should end up on the dashboard.
  • Creating an Analytics property when not having the https://www.googleapis.com/auth/analytics.edit scope yet. Expected experience:
    • Upon clicking the button, a dialog opens informing the user that they will need to grant additional permissions.
    • Once they click that button, they’re redirected to OAuth (should be mocked).
    • When returning, their original action is automatically invoked, without requiring them to click the button again.
    • They should end up on the dashboard.
  • Creating an Analytics view when not having the https://www.googleapis.com/auth/analytics.edit scope yet. Expected experience should match the one for creating an Analytics property above.

Implementation Brief

• Create a new write-scope-requests.test.js in tests/e2e/specs/modules/analytics
• Implement a new describe for Analytics write scope requests
• In a beforeAll, ensure that any oAuth requests are intercepted and successfully returned. See this example. Also ensure that any requests to the Analytics TOS as are also mocked and returned successfully.
• In the beforeEach, ensure that the Analytics module is set up by adding the following helpers:
  • activatePlugin( 'e2e-tests-oauth-callback-plugin' )
  • setSiteVerification()
  • setSearchConsoleProperty()
  • setupAnalytics()
• Write tests fulfilling the requirements as indicated in the AC.

QA Brief

Changelog entry

• N/A

[aaemnnosttv]

@felixarntz I’ve updated the AC for the first case (account provisioning) as mentioned above to only test up until the redirect to the TOS. This is because it would require more substantial changes to only test the gatoscallback handler which is already well tested in PHPUnit.

[tofumatt]

Code here looks good to me and the tests behave appropriately, so moving to approval.