Fix a11y issue where all pinnies are inaccessible to screenreaders

Opening this PR for visibility and greater discussion about a11y and our plugin architecture

Changes

Pinny sets aria-hidden = true to its lockup container, causing it to be unreadable by screenreaders
This hack of a fix leverages #x-root to determine page content that must be hidden instead of using the lockup container
Outstanding Issues
This hack only works for Mobify projects using the #x-root wrapper convention
This hack was applied for CCL (on a Zepto-compatible codebase), but it affects all Pinnies across all sites
There's an edge case where if the Pinny uses appendTo to append itself inside #x-root then it'll be hidden
Lockup does not have a way of having multiple containers within it, that could be leveraged in situations like this by Pinny (or another plugin)
Why are Lockup and Shade separate plugins when they're only ever used alongside Pinny??
How to Test
Bring in this branch's code for Pinny on a Mobify project
Test whether Pinnies in the project are a11y compliant