[feature] add support for Advanced Matching with the Pixel

The Facebook pixel has an advanced matching feature that enables you to send your customer data through the pixel but to enable this feature, we need to modify the default FB pixel code to pass data into the pixel init call. see https://developers.facebook.com/docs/facebook-pixel/pixel-with-ads/conversion-tracking#advanced_match
```js
fbq('init', '', {
em: '',
ph: '',
fn: ''
...
})
```

The issue names the Facebook Pixel integration but no repository files or tests. Start by locating the integration’s default fbq('init', ...) entry point and compare it with the linked Advanced Matching requirements. Done means the init call can receive the requested customer fields without breaking existing pixel setup, with coverage for the new behavior.

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