test: Add unit, component and integration tests for kyma companion

[chriskari]

Description

Changes proposed in this pull request:

• added unit test for formatMarkdown functions
• added component tests for Bubbles, Message, ErrorMessage, TasksList, CodePanel
• added integration test for companion's main functionalities

Related issue(s)

Definition of done

• The PR's title starts with one of the following prefixes:
  • feat: A new feature
  • fix: A bug fix
  • docs: Documentation only changes
  • refactor: A code change that neither fixes a bug nor adds a feature
  • test: Adding tests
  • revert: Revert commit
  • chore: Maintainance changes to the build process or auxiliary tools, libraries, workflows, etc.
• Related issues are linked. To link internal trackers, use the issue IDs like backlog#4567
• Explain clearly why you created the PR and what changes it introduces
• All necessary steps are delivered, for example, tests, documentation, merging

[mrCherry97]

I'll suggest to separate companion integration test to separate files, for example kompanion-suggestions, companion-error-handling etc, because this file is giant and problematic to debug in the future