feat: Error handling for companion

[chriskari]

Description

Changes proposed in this pull request:

• errors are now only handled after the final chunk was received, not with intermediate steps
• retry-button is only displayed if final chunk has property error !== null or every single chunk has status === "error"
• remove handleError from follow-ups
• display error notice next to user's messages that cause an error and have not been retried

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

[OliwiaGowor]

Suggested change

	throw new Error('No follow-up qeustions available');
	throw new Error('No follow-up questions available');