Make e2e compatible with headless

[Miraeld]

Is your feature request related to a problem? Please describe.
Yes, the problem is related to the inconsistency in the environments where the end-to-end (e2e) tests are run. Currently, the tests are run on the local environments of individual team members, which can lead to inconsistencies and different issues due to the variations in each person's setup.

Describe the solution you'd like
The proposed solution is to make the e2e tests compatible with headless mode. This would allow us to run the tests within a Docker container, ensuring a consistent testing environment for all team members, regardless of their local setup. The changes required to enable headless mode include adding a new ENV_HEADLESS environment variable and updating the Chromium launch configuration to use this variable.

Describe alternatives you've considered
An alternative solution could be to standardize the local testing environments of all team members. However, this would require significant effort and may not completely eliminate the inconsistencies due to variations in hardware, operating system, and other factors.

Additional context
Making the e2e tests compatible with headless mode would not only improve the consistency of the test results but also make it easier to integrate the tests into a continuous integration/continuous deployment (CI/CD) pipeline. This would allow us to automatically run the tests whenever changes are made to the codebase, further improving the reliability of our software.