Update sanitizer for auto-lightbox disabling to target root element instead of body

[westonruter]

Feature Description

Based on ampproject/amphtml#37854 (comment) it turns out that now if you add data-amp-auto-lightbox-disable to the root html element, not only will the auto-lightbox behavior be disabled but also the auto-lightbox script will also be prevented from being autoloaded. So we need to update AMP_Auto_Lightbox_Disable_Sanitizer (introduced in #6936 for #5122) to make that change.

Acceptance Criteria

The data-amp-auto-lightbox-disable attribute should be added to the html element instead of the body element.

Implementation Brief

No response

QA Testing Instructions

No response

Demo

No response

Changelog Entry

No response

[pooja-muchandikar]

QA Passed ✅

data-amp-auto-lightbox-disable attribute is shown in HTML tag instead of body tag.

Before: data-amp-auto-lightbox-disable attribute in body tag

---

After: data-amp-auto-lightbox-disable attribute in HTML tag

---