Follow-up from "Draft: feat: migrate GlProgressBar"

The following discussion from !4666 (merged) should be addressed:

• @vanessaotto started a discussion: (+1 comment)

  nit: In VS Code, I have the axe-linter installed and it shows this message. I'm not sure how relevant that is. The Cypress Axe specs in the codebase are happy with it. Also, it seems to be the same HTML as before. We could think about using progress instead. But to focus on migrating only, I'd be happy to do this rather as a follow up.