Instantiate ert config before starting everest server

[DanSava]

Issue
Resolves #9200

Approach
Instantiate ert_confg from everest config before we start everest server and report expectations as config validation error.

• PR title captures the intent of the changes, and is fitting for release notes.
• Added appropriate release note label
• Commit history is consistent and clean, in line with the contribution guidelines.
• Make sure unit tests pass locally after every commit (git rebase -i main --exec 'pytest tests/ert/unit_tests -n logical -m "not integration_test"')

When applicable

• When there are user facing changes: Updated documentation
• New behavior or changes to existing untested code: Ensured that unit tests are added (See Ground Rules).
• Large PR: Prepare changes in small commits for more convenient review
• Bug fix: Add regression test for the bug
• Bug fix: Create Backport PR to latest release

[StephanDeHoop]

Two small questions/comments, for the rest looks good to me. Also, I haven't checked out the code and somehow fail to search for it in the checks/pipeline (if you have a tip on how to search it, please let me know :p), but does this test ("test_starting_not_in_folder") now fail since we do validation earlier or did I misunderstood the discussion on the issue?

[StephanDeHoop]

Is this necessary? Or am I missing something (or is it a better safe than sorry)?

[DanSava]

This is fixing a small bug I noticed while testing out the functionality. But I guess it should not be part of this PR I will add it in a separate PR.

[DanSava]

Two small questions/comments, for the rest looks good to me. Also, I haven't checked out the code and somehow fail to search for it in the checks/pipeline (if you have a tip on how to search it, please let me know :p), but does this test ("test_starting_not_in_folder") now fail since we do validation earlier or did I misunderstood the discussion on the issue?

test_starting_not_in_folder will not fail if we do the validation earlier. That one test does not really start the everest server it is mocking the behaviour and will not be affected by this change.

Also, you are having trouble finding the tests because it is an integration tests and those tests are run using this command pytest tests/everest -n 4 -m "integration_test" --dist loadgroup (from .github/workflows/test_everest.yml) and this will not output individual test results from the files that have run. Maybe we should consider having a more verbose output for the integration tests as well.