PREOPS-5286: Add Playwright end-to-end tests

[alserene]

Created Playwright end-to-end tests for different operational modes. Documentation for installation, execution, and debugging is in playwright_testing.rst.

Tests are disabled by default to minimise workflow runtime and prevent artifact failures due to server load variations. To run tests manually, set ENABLE_PLAYWRIGHT_TESTS=1.

[alserene]

@ehneilsen I'm not too sure how to fix the workflow errors ModuleNotFoundError: No module named 'playwright'. Any ideas?

I added

- name: Install playwright browsers
        run: |
          pip install playwright
          python -m playwright install --with-deps

to test_and_build.yaml and I also added playwright to test-requirements.txt.
Playwright is now showing up in the Conda list, but, still, the error appears.

I'm not super familiar with GitHub workflows so this could be a trivial solve.

One fix (which doesn't solve this problem, only works around it) is to add conditional statements to the Playwright import statement (see 7c29363).

[alserene]

@ehneilsen There is also this error. I want to check with you if this code correction should be made here since this file was not modified in this PR.

schedview/app/scheduler_dashboard/scheduler_dashboard.py:273:12: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
    |
[27](https://github.com/lsst/schedview/actions/runs/9788750126/job/27027344464?pr=95#step:3:29)2 |         # Current fix for _conditions.mjd having different datatypes.
273 |         if type(self._conditions._mjd) == np.ndarray:
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ E721
274 |             self._conditions._mjd = self._conditions._mjd[0]

[ehneilsen]

@ehneilsen There is also this error. I want to check with you if this code correction should be made here since this file was not modified in this PR.

schedview/app/scheduler_dashboard/scheduler_dashboard.py:273:12: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
    |
[27](https://github.com/lsst/schedview/actions/runs/9788750126/job/27027344464?pr=95#step:3:29)2 |         # Current fix for _conditions.mjd having different datatypes.
273 |         if type(self._conditions._mjd) == np.ndarray:
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ E721
274 |             self._conditions._mjd = self._conditions._mjd[0]

Fixing this to use is instead of == would be fine.

[ehneilsen]

@ehneilsen I'm not too sure how to fix the workflow errors ModuleNotFoundError: No module named 'playwright'. Any ideas?

It looks like you figured this out? I see that the playwright tests are being run in the github CI, and that they are making it some way into the tests (with several asserts being passed successfully) before failing here.

[ehneilsen]

Looks good.