Reference tests integration: Expire 1p tracking cookies tests

[kdzwinel]

Reviewer: @sammacbeth

Description:

Integration of first party cookie expiry tests - https://github.com/duckduckgo/privacy-reference-tests/tree/main/expire-first-party-tracking-cookies.

Steps to test this PR:

1. Only tests are affected so as long as they are passing and code looks ok we should be good.

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