POC: use gitlab-qa to create an omnibus with aigw and run VSCode tests against it

To verify whether it is feasible to run VSCode IDE tests in the gitlab monolith pipeline.

❓	Answer
Manual smoke test - code suggestion	✅ responds with prompt
Manual smoke test - duo chat	✅ - responds with mock
Will tests need to be modified?	See #520658 (comment 2369651502)
Will mocks need to be modified?	I don't think so, perhaps for Duo Workflow if required, but this test only opens the webview currently
What token will be needed?	We need a valid token for the GitLab instance under test, since the instance has access to Duo, any token should be OK
We would need to somehow obtain a PAT for a test user before kicking off the VSCode tests	We can use the DEFAULT_ADMIN_API_TOKEN, since the AI gateway is mock response mode
How do we obtain the gitlab URL?	The current omnibus tests use http://gitlab.test, but when running locally this doesn't work for me 🤔 However, http://localhost:32769 works locally. Perhaps this is a mac problem, we may just have to try it in CI https://stackoverflow.com/questions/40125571/docker-for-mac-hostname-setup-for-container
Limitations	OAuth is not implemented for SM #509257 (comment 2371749445)

Steps to run VSCode extensions tests against a GitLab Self Managed omnibus instance (integrated with ai-gateway in mock response mode

From the monolith repo:

cd qa
bundle install
# the following uses the nightly image, but there are env variables to use different images/versions of gitlab
CHROME_DISABLE_DEV_SHM=true  DOCKER_DEFAULT_PLATFORM=linux/amd64 GITLAB_QA_ACCESS_TOKEN=<i think this is just an access token to download the docker images> GITLAB_LICENSE_MODE=test QA_EE_ACTIVATION_CODE=1Password bundle exec gitlab-qa Test::Integration::AiGateway EE --no-tests

From the vscode repo:

<from the vscode ext dir>
cd test/e2e
❯ E2E_GITLAB_HOST=http://localhost:32769 TEST_GITLAB_TOKEN=<see link below for token> npm run test:e2e

Token value

Some tests will fail, see: #520658 (comment 2369651502)

Summary

A subset of the VSCode E2E tests from https://gitlab.com/gitlab-org/gitlab-vscode-extension/-/tree/main/test/e2e can run successfully against an Omnibus instance of GitLab configured to communicate to an ai gateway in mock response mode.

The same DEFAULT_ADMIN_API_TOKEN can be used for these tests, there is a question over which host we will need to use, locally I had to use http://localhost:32769 but in CI we may be able to use http://gitlab.test

OAuth will not work in this set-up as it is not implemented in the vscode extension for SM instances yet