fix(overlays): hide the focus trap div from screen readers (#29970)

Issue number: resolves #29858

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## What is the current behavior?
When swiping between elements using Android TalkBack, a green box is
shown for certain overlays and it gains focus at the beginning and end
of those overlays:

<img width="419" alt="Screenshot 2024-10-25 at 2 44 45 PM"
src="https://github.com/user-attachments/assets/dffd8126-ec1d-4b6f-87fc-6488c7c09aab">

## What is the new behavior?
The `aria-hidden` attribute is now added to the focus trap divs to hide
them from screen readers, without preventing these divs from trapping
keyboard focus.

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

## Other information
Dev build: `8.3.4-dev.11729882231.1b2e7f13`