ci: improved e2e tests in order to work in ubuntu-latest pipeline again (#2048869)

[rH4rtinger]

Please check before merging

• Is the content of the README.md file still up-to-date?
• Have you added an entry to the CHANGELOG.md?
• Is the pull request title written in the Conventional Commits format?
• VSCode: Did you write e2e tests?
• VSCode: Did you follow the UX Guidelines?

Description

fixed github pipeline in order to execute e2e tests again:

• replaced VSBrowser.instance.openResources with other (native) VSCode options, because it does no longer work on ubuntu-24, see [🚫 Bug] openResources() not working on Ubuntu 24.04 redhat-developer/vscode-extension-tester#1701
• removed node 18 in the node versions, because it is quite an old version
• changed sonar action to the non deprecated action
• moved some tests classes, in order to execute the webview tests before the command tests. It was the other way around before my change, and the pipeline no longer worked. Swapping those was a logical thing, because in the command tests there is also the webview needed to create the config. If the config tests are not working, the other tests might also not work
• only opened the workspace once per all tests
• adding some force in order to remove some folders during the tests

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
2.0% Duplication on New Code

See analysis details on SonarQube Cloud