Focus not trapped in detached mode

## Description

when in detached mode (fullscreen or modal), focus should be trapped.

## Reproduction

**Steps**

1. Go to https://www.algolia.com/doc/ui-libraries/autocomplete/introduction/what-is-autocomplete/
2. Reduce viewport width to 500px to switch to detached mode.
3. Click on the first autocomplete.
4. Press Tab a couple of times (or Shift+Tab)
5. Some hidden element is focused, and modal can't be closed with Esc anymore

## Expected behavior

focus should be trapped.

## Environment

- OS: [e.g. Windows / Linux / macOS / iOS / Android]
- Browser: [e.g. Chrome, Safari] Firefox 88
- Autocomplete version: [e.g. 1.0.0] 1.0.1

Reproduce the issue at the linked Autocomplete documentation page by reducing the viewport to 500px and opening the first autocomplete. Start by tracing the detached-mode focus handling; done means Tab and Shift+Tab keep focus within the modal and Escape can still close it.

Written by the indexing model from the issue text.