[Accessibility] View and analyze... expand: Focus jumps to left navigation after expanding section, preventing keyboard users from accessing the expanded content

**What is broken?**

| Behavior | Details |
|--------------|---------|
| **Actual** | After activating the "View and analyze your data using dashboards" expand button via keyboard, focus jumps to the left side navigation (Dashboards item) instead of staying on or moving into the newly expanded content. Keyboard users cannot access the expanded section without re-navigating from the top. |
| **Expected** | After expanding the section, focus should remain on the expand button or move to the first focusable element within the expanded content, so keyboard users can immediately interact with the newly revealed options. |

**Steps to reproduce**
1. Go to Security -> Get started page.
2. Use keyboard and navigate to View and analyze... expand button.
3. Activate it.
4. Press Tab key few times.
5. Observe that focus moves to left side of the page instead of moving to the expanded content.

**Screenshot / recording**

https://github.com/user-attachments/assets/95016ac4-5734-42c6-92fa-4fa841ebd92a

**WCAG criterion**

- [Understanding SC 2.4.3 Focus Order (Level A)](https://www.w3.org/WAI/WCAG22/Understanding/focus-order.html)

**Potential solution / additional context (optional)**

After the section expands, focus should be programmatically kept on the expand button or moved to the first interactive element within the expanded content, preventing it from jumping to an unrelated part of the page.
Related to: https://github.com/elastic/kibana-team/issues/3927.

**Environment**
| Setting | Value |
|-----------------------------------|-------|
| **Kibana version** | 9.5.0 |
| **Browser (optional)** | Chrome |
| **Operating system (optional)** | macOS Tahoe |
| **Screen reader (if applicable)** | - |