updates email.js to correctly handle the klaviyo object promise

[cykolln]

Description

addresses #306 by adding the correct handling for the promise returned from klaviyo.isIdentified(). This fixes a bug where we weren't correctly identifying profiles from the checkout page.

Manual Testing Steps

1. tested new behavior on a local magento site, valildated the klaviyo profile was correctly created.

Pre-Submission Checklist:

• You've updated the CHANGELOG following the steps here
• Internal Only - If this is a release, please confirm the following:
  • The links in the changelog have been updated to point towards the new versions
  • The version has been incremented in the following places: module.xml and composer.json

NOTE: Please use the Changelogger cli tool to manage versioned file upgrades.

[smoucka]

lgtm