Add tests for the text editor and related files

[LawrenceBorst]

Fixes Lundalogik/crm-feature#4076

Review:

• [ ] Commits are atomic
• [ ] Commits have the correct type for the changes made
• [ ] Commits with breaking changes are marked as such

Browsers tested:

(Check any that applies, it's ok to leave boxes unchecked if testing something didn't seem relevant.)

Windows:

• [ ] Chrome
• [ ] Edge
• [ ] Firefox

Linux:

• [ ] Chrome
• [ ] Firefox

macOS:

• [ ] Chrome
• [ ] Firefox
• [ ] Safari

Mobile:

• [ ] Chrome on Android
• [ ] iOS

[github-actions[bot]]

Documentation has been published to https://lundalogik.github.io/lime-elements/versions/PR-2983/

[LawrenceBorst]

It wasn't yet possible to add tests for the prosemirror adapter, as we run into an error related to unified

    export {unified} from './lib/index.js'
    ^^^^^^

    SyntaxError: Unexpected token 'export'

[lime-opensource]

:tada: This PR is included in version 37.45.0 :tada:

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot :package::rocket: