refactor: Use live region component in progress bar

[Al-Dani]

Description

Remove dynamic aria live component and restore initial live region component structure.
Use live region component in progress bar directly.

Follow-up for #555

How has this been tested?

Manually with screen reader.
New unit test added

Review checklist

The following items are to be evaluated by the author(s) and the reviewer(s).

Correctness

• Changes include appropriate documentation updates.
• Changes are backward-compatible if not indicated, see CONTRIBUTING.md.
• Changes do not include unsupported browser features, see CONTRIBUTING.md.
• Changes were manually tested for accessibility, see accessibility guidelines.

Security

• If the code handles URLs: all URLs are validated through the checkSafeUrl function.

Testing

• Changes are covered with new/existing unit tests?
• Changes are covered with new/existing integration tests?

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[codecov]

Codecov Report

Base: 92.83% // Head: 92.84% // Increases project coverage by +0.00% 🎉

Coverage data is based on head (bb9df9c) compared to base (9476ae4).
Patch coverage: 95.45% of modified lines in pull request are covered.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #619   +/-   ##
=======================================
  Coverage   92.83%   92.84%           
=======================================
  Files         572      569    -3     
  Lines       16476    16466   -10     
  Branches     4530     4527    -3     
=======================================
- Hits        15296    15288    -8     
+ Misses       1104     1102    -2     
  Partials       76       76           

Impacted Files	Coverage Δ
src/internal/components/live-region/index.tsx	95.83% <93.33%> (+12.50%)	⬆️
src/progress-bar/index.tsx	100.00% <100.00%> (ø)

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