feat: use tabbable shadow dom support

[scomea]

📖 Description

This pr updates the dialog and toolbar elements to use tabbable's new shadom dom support.

🎫 Issues

Removes some local code.

👩‍💻 Reviewer Notes

📑 Test Plan

• todo: add some shadow dom tests for dialog/toolbar, ideally in play wright.

✅ Checklist

General

• I have included a change request file using $ yarn change
• I have added tests for my changes.
• I have tested my changes.
• I have updated the project documentation to reflect my changes.
• I have read the CONTRIBUTING documentation and followed the standards for this project.

Component-specific

• I have added a new component
• I have modified an existing component
• I have updated the definition file
• I have updated the configuration file

[stale]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stefcameron]

FYI, tabbable v5.3.0 and focus-trap v6.8.0 with Shadow DOM support have been published to NPM. I hope it helps for this!

[chrisdholt]

@scomea let's get this up to date, I'd like to see if we can get this in for the final versions of fast-components.

[janechu]

Due to draft status, conflicts, and potential issues with this PR being fairly out of date we're closing as part of #6951.