Add canvas tutorial button highlight

**User story**
As a user I would like a way to see where I currently am in the tutorial.

**Describe the solution you'd like**
Highlight the button that belongs to the section I am reading.

**Additional context**
The highlight was previously a feature, but did not work as intended since it only changed the highlight when a button was clicked and not when scrolling. At this time CanvasTutorialSectionButton.tsx contains the code for the previous implementation.

**Development checklist**

- [ ] [Threat Modeling](https://cheatsheetseries.owasp.org/cheatsheets/Threat_Modeling_Cheat_Sheet.html)

Start by reading CanvasTutorialSectionButton.tsx, which contains the previous implementation. Trace how tutorial sections and scrolling are represented, then verify that the button for the section currently being read stays highlighted as the user scrolls, not only after a button click.

Written by the indexing model from the issue text.