ContextualHelp with scrollbar is not keyboard accessibile

### Provide a general summary of the issue here

I have a ContextHelp which can be long and at times displays a vertical scrollbar.
It is not possible to get to the content at the bottom using just a keyboard.

### 🤔 Expected Behavior?

Should be able to scroll the help content with the keyboard

### 😯 Current Behavior

Can not scroll the help content with the keyboard.

### 💁 Possible Solution

_No response_

### 🔦 Context

_No response_

### 🖥️ Steps to Reproduce

Reduce the height of your browser window.
Run https://reactspectrum.blob.core.windows.net/reactspectrum/169b0467b0c1a2638bee97d25cd432c45f27cfc8/storybook/index.html?path=/story/contextualhelp--default&providerSwitcher-express=false
and keyboard to the button. Press the button.


### Version

3.31.0

### What browsers are you seeing the problem on?

Firefox, Chrome, Safari, Microsoft Edge

### If other, please specify.

_No response_

### What operating system are you using?

macOs

### 🧢 Your Company/Team

Adobe/Admin Console

### 🕷 Tracking Issue

_No response_