fix cpcss tests, updated background to do fresh activation

[Mai-Saad]

Description

• updated background to have fresh install
• updated selector for cpcss
• added CPCSS Tto scripts to run tests in isolation

Fixes #166
Explain how this code impacts users.

Type of change

• New feature (non-breaking change which adds functionality).
• Bug fix (non-breaking change which fixes an issue).
• Enhancement (non-breaking change which improves an existing functionality).
• Breaking change (fix or feature that would cause existing functionality to not work as before).
• Sub-task of #(issue number)
• Release

Detailed scenario

Explain how to reproduce the issue (for bugs) or how to trigger the new code. You can refer to the GitHub issue or grooming if it is still applicable.
fixes #166

Technical description

As per grooming + added test isolation / fresh install

Documentation

As gromming

New dependencies

No

Risks

None

Mandatory Checklist

Code validation

• I validated all the Acceptance Criteria. If possible, provide screenshots or videos.
• I triggered all changed lines of code at least once without new errors/warnings/notices.
• I implemented built-in tests to cover the new/changed code.

Code style

• I wrote a self-explanatory code about what it does.
• I protected entry points against unexpected inputs.
• I did not introduce unnecessary complexity.
• Output messages (errors, notices, logs) are explicit enough for users to understand the issue and are actionnable.

Additional Checks

• In the case of complex code, I wrote comments to explain it.
• When possible, I prepared ways to observe the implemented system (logs, data, etc.).
• I added error handling logic when using functions that could throw errors (HTTP/API request, filesystem, etc.)

[Mai-Saad]

cpcss report

smoke test report on PR

[Mai-Saad]

Remain, for this scenario, we shall log in with admin 2, currently, we use the same user to login => we can open GH for that

  Scenario: Shouldnot display the CPCSS banner to admin 2 if it was dismissed by admin 1
    Given I have an unexpired account
    And turn on 'CPCSS'
    Then I must see the banner 'We highly recommend the updated Remove Unused CSS for a better CSS optimization. Load CSS Asynchronously is always available as a back-up.'
    When click on 'Turn on Remove Unused CSS'
    Then I must see the banner 'The Remove Unused CSS service is processing your pages'
    When I connect as 'admin2'
    And I go '/wp-admin/options-general.php?page=wprocket#file_optimization'
    Then I must not see the banner 'We highly recommend the updated Remove Unused CSS for a better CSS optimization. Load CSS Asynchronously is always available as a back-up.'

[hanna-meda]

Thank you, @Mai-Saad, for this PR.
All looks good and running npm run test:cpcss all tests pass.