Fix customer custom properties KlaviyoV3Api.php

[JamesFX2]

Hey, you've formatted the properties incorrectly, in the profile object, in properties is a child of data / attributes - see https://jsonformatter.org/fa628e for reference which was taken from the API example on Klaviyo

Description

Fixes bug with sending custom data on a profile to Klaviyo events API

Manual Testing Steps

This is an event we sync to Klaviyo that updates a customer profile. This field is no longer updating the contact. I've checked the API documentation and I have found this bug.

 {"data":{"type":"event","attributes":{"properties":{"$value":null},"time":"2024-02-06T13:46:34","value":null,"metric":{"data":{"type":"metric","attributes":{"name":"Customer Sync","service":"magentotwo"}}},"profile":{"data":{"type":"profile","attributes":{"email":"[email protected]","first_name":"Leila","last_name":"Test"},"properties":{"$first_name":"Leila","$last_name":"Test","email":"[email protected]","$nhs_last_date":"2024-02-06","nhs_last_date":"2024-02-06"}}}}}}

[cykolln]

Thanks for catching this, can you please update the Changelog and add this fix under Unreleased. We will include it in a release this week.

[JamesFX2]

@cykolln sorry, are you talking to me?

[cykolln]

@cykolln sorry, are you talking to me?

@JamesFX2 Yes, sorry!

[JamesFX2]

Added requested changes @cykolln

Reviewer OOO

[jordanleslie]

Added requested changes @cykolln

Once CI is passing i'll merge this in.

[cykolln]

@JamesFX2 Hey! Looks like precommit is failing for this PR - locally you can run pre-commit run --all-files to resolve. We can get this merged in as soon as CI is passing.