Automate testing an ability to disable "Install from VSIX..." functionality

[martinszuc]

What does this PR do?

This PR adds a comprehensive end-to-end test that validates the ability to disable "Install from VSIX..." functionality in DevSpaces workspaces through ConfigMap configuration. The test implements the complete U77 test scenario and verifies:

When VSIX installation is disabled:

• "Install from VSIX" command is not available in Command Palette (F1 menu)
• "Install from VSIX" action is not available in Extensions view More Actions menu
• "Install Extension VSIX" action is not available in Explorer context menu for .vsix files
• Default VSIX extensions are NOT auto-installed during workspace startup
• Proper notification is displayed when VSIX installation is disabled

When VSIX installation is enabled (regression test):

• All "Install from VSIX" UI elements are properly available
• Default VSIX extensions ARE auto-installed during workspace startup
• Existing functionality works as expected

The test includes new page objects and utilities for:

• CommandPalette - For testing command palette interactions
• ExtensionsView - For testing extensions view menu interactions
• ExplorerView - For testing file explorer context menu interactions
• NotificationHandler - For checking workspace notifications
• ConfigMap management utilities for test setup and cleanup

Screenshot/screencast of this PR

What issues does this PR fix or reference?

https://issues.redhat.com/browse/CRW-8655

How to test this PR?

1. Run the test:

export USERSTORY=VsixInstallationDisableTest
export NODE_TLS_REJECT_UNAUTHORIZED=0
export TS_OCP_LOGIN_PAGE_PROVIDER_TITLE=htpasswd
export TS_SELENIUM_VALUE_OPENSHIFT_OAUTH=true
export TS_SELENIUM_HEADLESS=false
export OCP_VERSION=4.18
export TS_SELENIUM_BASE_URL=https://devspaces.apps....
export OCP_CONSOLE_URL=https://console-openshift-console.apps.....
export TS_SELENIUM_OCP_PASSWORD=
export TS_SELENIUM_OCP_USERNAME=

npm run test

PR Checklist

As the author of this Pull Request I made sure that:

• The Eclipse Contributor Agreement is valid
• Code produced is complete
• Code builds without errors
• Tests are covering the bugfix or new feature
• The repository devfile is up to date and works
• Sections What issues does this PR fix or reference and How to test this PR completed
• Relevant user documentation updated
• Relevant contributing documentation updated
• CI/CD changes implemented, documented and communicated

Reviewers

Reviewers, please comment how you tested the PR when approving it.

[dmytro-ndp]

Commonly PR looks good to merge, with a few non-critical notices.

Well done, @martinszuc !

[ibuziuk]

@martinszuc @dmytro-ndp are we good to merge?

[martinszuc]

@martinszuc @dmytro-ndp are we good to merge?

@ibuziuk No it's not, code needs some refactoring and cleanup according to dmytros comment.

I plan to take a look during weekend. So probably it should be ready by Monday.

[martinszuc]

If reviewers have nothing more to add, the PR is READY for merge from my side :)