Side nav not sticky when switching options

[fbd399]

Summary of the bug

When on a page selected from the side nav, if a user selects a different page from the side nav, the side nav scroll memory is lost and it scrolls back to top.

How to reproduce

1. Go to the Components tab
2. Scroll down the side nav and choose one of the last options
3. Now select a different option (component page)
4. The side nav will now appear scrolled all the way to the top

🧐 Expected behaviour

Preferred behaviour (to reduce cognitive load and familiarity of navigation and position) dictates that the side nav's scroll should stay fixed.

Refer to any major Design System website:

• Cloudscape
• MUI
• Carbon
• Duet

📸 Screenshots or code

[MI6-255]

Now scrolls to position with delay, still worth seeing if we can fix the delay