Add information on how to verify if a user is part of 1% experimental group

[mohdsayed]

Description

Add information in the "Facilitated Testing" page on how to verify if a user is part of a 1% experimental group.

Relevant Technical Choices

• If navigator.cookieDeprecationLabel API is not available, the browser is not part of a group as mentioned in Accessing the cookieDeprecationLabel JavaScript API. When tested, this API is not available even when user is part of the experiment group, therefore we decided to only showing a message.

Testing Instructions

• Open PSAT panel and visit "Facilitated Testing" section and look at the "Membership In Experiment Group"
• Refer to the screenshots section below for the message

Additional Information:

This article also suggests the following

For browsers in the 1% group, users will get a new chrome://settings/trackingProtection page instead of chrome://settings/cookies:

Screenshot/Screencast

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Checklist

• I have thoroughly tested this code to the best of my abilities.
• I have reviewed the code myself before requesting a review.
  This code is covered by unit tests to verify that it works as intended. NA
  The QA of this PR is done by a member of the QA team (to be checked by QA). NA

Fixes #504

[mohdsayed]

Observation:

• navigator.cookieDeprecationLabel is not available even when browser is part of 1%, so we may have two possible options.
  • Ask the user to visit a webpage with third-party cookies and parse the console error to find out if the cookies are actully getting blocked.
    • Without Membership (and with third-party enabled) from settings we get the following console error - “Third-party cookie will be blocked. Learn more in the Issues tab.”
    • When third-part cookies are blocked from settings (When not part of the membership) - No errors are shown.
    • When part of the membership - “Blocked third-party cookie. Learn more in the Issues tab”.
  • Just provide the information shared in this article
    • “For browsers in the 1% group, users will get a new chrome://settings/trackingProtection page instead of chrome://settings/cookies:”