[Morse Chat Tutorial] Keyboard Navigation: "What is Morse code?" Section Cannot Be Expanded Using Enter or Space

Describe the bug
In the Morse Chat tutorial, the "What is Morse code?" expandable section can receive keyboard focus, but it cannot be expanded using the keyboard(Enter or Space).

Steps to reproduce the behavior:

1. Navigate to Microsoft MakeCode for micro:bit.
2. Scroll to the Tutorials for the new micro:bit (V2) section.
3. Use Tab to move focus to the Morse Chat tutorial card.
4. Press Enter to open the tutorial.
5. Continue using Tab until focus moves to the "What is Morse code?" expandable section.
6. Press Enter or Space.
7. Observe the behavior of the section.

Actual behavior
The "What is Morse code?" section receives keyboard focus, but pressing Enter or Space does not expand the content.

Expected behavior
The "What is Morse code?" section should expand and collapse when activated using Enter or Space, allowing keyboard-only users to access the content in accordance with standard accessibility expectations for expandable controls.

Screenshots

Additional context
1.OS: Windows 11 25H2 & Mac Mini M2 macOS Tahoe 26.5.2
2.Browser: Chrome, Edge, Firefox, and Safari
3.makecode.microbit.org version: 9.0.3
4.Microsoft MakeCode version: 13.0.3

Start by opening the Morse Chat tutorial and locating the "What is Morse code?" expandable section and its activation handling. Reproduce the issue with keyboard focus, then verify that Enter and Space expand and collapse the section and that the content is accessible to keyboard-only users.