[Draft] Unit Test for dashboard

[proy30]

This PR introduces the first unit test for the ImpactX dashboard, leveraging the SeleniumBase library to simulate a simulation run by a user with the GUI.

Key Features

• The unit test runs a simulation using the parameters from the FODO cell example on the GUI. (takes ~1 minute)
• The test is considered successful if the simulation is completed without errors.

Issues

• ~~Dependency on Running Dashboard:~~
  • ~~The current implementation requires the ImpactX dashboard to run in a separate terminal before executing the test via pytest.~~
  • ~~Can investigate to potentially have dashboard be launched within the test itself.~~
  • ~~Unit test is flaky with passing/failing, unsure if this is due to code error or error in pytest implementation. Need to investigate. Started occurring after the implementation of subprocess.~~
• Adding seleniumbase as a dependency
  • Unsure where to add. (implemented incorrectly)

Checklist

• [X] Implement unit test for impactx-dashboard (testing with FODO cell simulation parameters.
• [X] Automate the dashboard launch within the test.
• [X] Fix flaky unit test
• [x] Include seleniumbase dependency in CI test files
• [x] Include trame dependencies in CI test files
• [ ] Fix headless state for ctest

Resolves #667