Improve Facebook Click to Load integration tests

[kzar]

Improve Facebook Click to Load integration tests

Improvements to the Facebook Click to Load integration tests,
including:

1. Reduce flaky failures by waiting until all the required extension
   configuration has been loaded.
2. Log requests using Puppeteer instead of relying on the test page
   to accurately report the number of allowed/blocked requests.
3. Test requests to the SDK are redirected properly.
4. Test that unblocking works correctly and that reloading the page
   restores blocking.

This change also:

• Renames and expands on the background waiting integration test
  helper module. That way, we can avoid duplicating configuration
  waiting logic.
• Tweaks the request logging helper module to avoid logging in-flight
  requests that started before a navigation but finished
  afterwards. That race condition was the cause of some test flakiness.
• Tweaks the YouTube CTL tests to wait for "networkidle0" instead of
  "networkidle2". That means waiting for all requests to complete,
  rather than all but two.

Reviewer: @jonathanKingston

CC: @ladamski, @Charlie-belmer, @sammacbeth, @kdzwinel
Depends on: #978

Description:

This change makes use of the YouTube Click to Load work to improve the Facebook Click to Load integration tests.

Steps to test this PR:

1. Run the integration tests (to do that locally type npm run test-int.

Automated tests:

• Unit tests
• Integration tests

Reviewer Checklist:

• Ensure the PR solves the problem
• Review every line of code
• Ensure the PR does no harm by testing the changes thoroughly
• Get help if you're uncomfortable with any of the above!
• Determine if there are any quick wins that improve the implementation

PR Author Checklist:

• Get advice or leverage existing code
• Agree on technical approach with reviewer (if the changes are nuanced)
• Ensure that there is a testing strategy (and documented non-automated tests)
• Ensure there is a documented monitoring strategy (if necessary)
• Consider systems implications

[kdzwinel]

Nicely done! I left some comments, mostly nits 👀

[kdzwinel]

Thanks! LGTM.