Fix frontend tests

[notoraptor]

Description

Fix failing frontend tests, last example here: https://github.com/Epistimio/orion/actions/runs/7137478292/job/19437604432

Changes

• Use latest version of selenium
• Update tests to correctly set Firefox browser to headless mode with latest version of selenium

Checklist

Tests

• [ ] I added corresponding tests for bug fixes and new features. If possible, the tests fail without the changes
• [ ] All new and existing tests are passing ($ tox -e py38; replace 38 by your Python version if necessary)

Documentation

• [ ] I have updated the relevant documentation related to my changes

Quality

• [ ] I have read the CONTRIBUTING doc
• [ ] My commits messages follow this format
• [ ] My code follows the style guidelines ($ tox -e lint)