[Dialog] Focus trap does not work properly when <sl-dialog> is in a shadow root

[danNordlogic]

Describe the bug

Rendering and opening an inside of a shadow root does not seem to play nice with the focus trap. I can tab out of the dialog into elements underneath it.
Ths problem was already raised here: #709 but it seems it's still not solved (using version 2.4.0).

To Reproduce

Steps to reproduce the behavior:

Create a new Lit project
Add shoelace as a dependency (or via CDN)
Use the example code from the documentation
Open the dialog and press tab. The focus will move to the button underneath.

Demo

Reproduction on CodeSandbox

Browser / OS

• OS: [e.g. Mac, Windows]
• Browser: Chrome Version 114.0.5735.111, Edge Version 114.0.1823.51

[claviska]

Here's a CodePen, for convenience: https://codepen.io/claviska/pen/bGQeWgY