feat: Add unitests for BrowserToolkit

[JoyceXu02]

Description

Added some unitests for BrowserToolkit, and updated a safer url extractor.

Checklist

Go over all the following points, and put an x in all the boxes that apply.

• [x] I have read the CONTRIBUTION guide (required)
• [x] I have linked this PR to an issue using the Development section on the right sidebar or by adding Fixes #issue-number in the PR description (required)
• [x] I have checked if any dependencies need to be added or updated in pyproject.toml and uv lock
• [x] I have updated the tests accordingly (required for a bug fix or a new feature)
• [x] I have updated the documentation if needed:
• [ ] I have added examples if this is a new feature Partially fixed #1752 If you are unsure about any of these, don't hesitate to ask. We are here to help!