fix: expose getHtml() to editor api

[silverkszlo]

📝 Summary

Exposing Tiptaps getHtml() in the editor API is needed to fix the insertion of tables in the Whiteboard App: nextcloud/whiteboard#902

🏁 Checklist

• Code is properly formatted (npm run lint / npm run stylelint / composer run cs:check)
• Sign-off message is added to all commits
• Tests (unit, integration and/or end-to-end) passing and the changes are covered with tests
• Documentation (README or documentation) has been updated or is not required

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[silverkszlo]

/backport to stable32

[silverkszlo]

/backport to stable31

[silverkszlo]

/backport to stable30

[silverkszlo]

/backport to stable29

[backportbot]

The backport to stable29 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable29
git pull origin stable29

# Create the new backport branch
git checkout -b backport/8080/stable29

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts, resolve them
git cherry-pick fea94e38

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/8080/stable29

Error: Failed to check for changes with origin/stable29: No changes found in backport branch

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Learn more about backports at https://docs.nextcloud.com/server/stable/go.php?to=developer-backports.