Spike on @vscode/test-* + vitest patterns for integration tests

[marcosnav]

Scope of spike
Create a couple tests for homeView that implement extensions integration testing as suggested by Microsoft, looking to include vitest for tests to be included in code coverage. Also determine if this is something that plays well with Positron.

Coverage tooling work to be done with #2488

Goal

1. A PR that serves as proposal and example pattern to keep crating more tests to increment coverage
2. After proposal discussed and accepted, create an epic issue and individual issues for homeView integration tests to cover processes and data flows currently untested.