"Scrollable region must have keyboard access" with focusable elements within

### Product

axe-core

### Product Version

4.10.3

### Latest Version

- [x] I have tested the issue with the latest version of the product

### Issue Description

#### Expectation
No warnings about scrollable regions needing keyboard access.

#### How to Reproduce
Open https://plnkr.co/edit/IyLmkiUknP2hB8jT?open=main.js&preview
Click the arrows at the top right to show the example in a separate window
Run the Axe Extension to scan the page.

#### Additional context
This grid is wrapped with a "tab guard" element (tabIndex 0) that manages which cell needs to be focused when the grid is focused, and then the cells (tabIndex -1) will scroll the grid with a custom scroll logic while moving focus across cells.

Start with the linked Plunker reproduction and run axe-core 4.10.3 against the grid after opening it in a separate window. Trace the check producing “Scrollable region must have keyboard access” and compare the tab guard and cell focus behavior described in the issue. Done means the valid grid no longer triggers this warning while unrelated scrollable regions are still reported.

Written by the indexing model from the issue text.