Investigate slow karma tests for `note_app`

FAILED TESTS:
  note_app
    update note
      individual note
        ✖ calls the service to update the note
          Chrome
        Failed: Test is running too long!
            at webpack:///builds/gitlab-org/gitlab-ce/spec/javascripts/test_bundle.js:113 <- spec/javascripts/test_bundle.bundle.js:1141426:10

      discussion note
        ✖ updates the note and resets the edit form
          Chrome
        Failed: Test is running too long!
            at webpack:///builds/gitlab-org/gitlab-ce/spec/javascripts/test_bundle.js:113 <- spec/javascripts/test_bundle.bundle.js:1141426:10

Seen in https://gitlab.com/gitlab-org/gitlab-ce/-/jobs/220320968

This is happening consistently in the last few pipelines in CE and EE

The global karma timeout has been increased to 4 seconds so these don't fail anymore. We should investigate / fix these tests though.