Stop "ERROR: TypeError{}" from being logged to the console and fail tests

What does this MR do?

• Add Vue.config.errorHandler which will stop ERROR: TypeError{} from being logged. It will also fail the tests if an error is encountered.
• Fix up notes spec that was patched over in our Vue upgrade.

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

For a detailed explanation, see https://gitlab.com/gitlab-org/gitlab-ce/issues/37619#note_50422859

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
  • Not user-facing
• Tests added for this feature/bug
• Review
  • Has been reviewed by Frontend
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• Internationalization required/considered

What are the relevant issue numbers?

Closes #37619 (closed)