Add Klaviyo query parameter to the list of stripped parameters in VCLs

[Gelmo]

Description (*)

• Related to Issue #35227
• Klaviyo's emails include the _kx query parameter.
• Klaviyo's services and modules are becoming more popular, so this query parameter should be stripped in the default Varnish configs provided with Magento.
• This PR adds _kx to the list of stripped parameters in the VCLs for Varnish 4, 5, and 6.

Related Pull Requests

• None

Fixed Issues (if relevant)

1. Fixes magento/magento2#35227

Manual testing scenarios (*)

• Use a VCL that is included with Magento.
• Send a marketing email via Klaviyo.
• Watch varnishlog.
• Visit the site using a link that is included in a Klaviyo-generated email.
• Visit the site using a similar link that does not include the _kx query parameter.
• Compare the results shown by varnishlog.
• Without this change in place, the request with the _kx parameter is served an uncached page.
• With this change in place, the request with the _kx parameter is served a cached page.

Questions or comments

• Our company (JetRails) has several clients that utilize Klaviyo's services for sending marketing emails. We noticed that visitors who came to the site from those emails were being served uncached pages. The adjustment in this PR has successfully resolved this issue for our clients.
• Klaviyo's services and modules are becoming more popular, so this query parameter should be stripped in the default Varnish configs provided with Magento.
• Please list myself and JetRails as the contributors once this has been merged.

Contribution checklist (*)

• [x] Pull request has a meaningful description of its purpose
• [x] All commits are accompanied by meaningful commit messages
• [x] All new or changed code is covered with unit/integration tests (if applicable)
• [x] README.md files for modified modules are updated and included in the pull request if any README.md predefined sections require an update
• [ ] All automated tests passed successfully (all builds are green)

[m2-assistant[bot]]

Hi @Gelmo. Thank you for your contribution Here are some useful tips how you can test your changes using Magento test environment. Add the comment under your pull request to deploy test or vanilla Magento instance:

• @magento give me test instance - deploy test instance based on PR changes
• @magento give me 2.4-develop instance - deploy vanilla Magento instance

:exclamation: Automated tests can be triggered manually with an appropriate comment:

• @magento run all tests - run or re-run all required tests against the PR changes
• @magento run <test-build(s)> - run or re-run specific test build(s) For example: @magento run Unit Tests

<test-build(s)> is a comma-separated list of build names. Allowed build names are:

1. Database Compare
2. Functional Tests CE
3. Functional Tests EE,
4. Functional Tests B2B
5. Integration Tests
6. Magento Health Index
7. Sample Data Tests CE
8. Sample Data Tests EE
9. Sample Data Tests B2B
10. Static Tests
11. Unit Tests
12. WebAPI Tests
13. Semantic Version Checker

You can find more information about the builds here

:information_source: Run only required test builds during development. Run all test builds before sending your pull request for review.

For more details, review the Magento Contributor Guide documentation.

:warning: According to the Magento Contribution requirements, all Pull Requests must go through the Community Contributions Triage process. Community Contributions Triage is a public meeting.

:clock10: You can find the schedule on the Magento Community Calendar page.

:telephone_receiver: The triage of Pull Requests happens in the queue order. If you want to speed up the delivery of your contribution, join the Community Contributions Triage session to discuss the appropriate ticket.

:pencil2: Feel free to post questions/proposals/feedback related to the Community Contributions Triage process to the corresponding Slack Channel

[Gelmo]

I am discussing the CLA with my employer, and I will re-create the PR as advised once the CLA has been read and signed.

[vasileuskidzmitry]

Hello @sdzhepa! Could you please advise how to get this pull request and ticket off the ground? I can take it upon myself and complete all the required steps.

[vasileuskidzmitry]

@magento run all tests

[magento-automated-testing[bot]]

The requested builds are added to the queue. You should be able to see them here within a few minutes. Please message the #magento-devops slack channel if they don't show in a reasonable amount of time and a representative will look into any issues.

[vasileuskidzmitry]

@magento run Functional Tests CE

[magento-automated-testing[bot]]

The requested builds are added to the queue. You should be able to see them here within a few minutes. Please message the #magento-devops slack channel if they don't show in a reasonable amount of time and a representative will look into any issues.

[vasileuskidzmitry]

@magento run Sample Data Tests CE, Sample Data Tests EE, Sample Data Tests B2B, Functional Tests CE

[magento-automated-testing[bot]]

The requested builds are added to the queue. You should be able to see them here within a few minutes. Please message the #magento-devops slack channel if they don't show in a reasonable amount of time and a representative will look into any issues.