build(deps): bump prosemirror-trailing-node to 2.0.8

[LoneRifle]

📝 Summary

Bump prosemirror-trailing-node to 2.0.8 to pick up remirror/remirror#2245, which drops @remirror/core-helpers.
The latter package was heavy, bringing in several additional dependencies, but was only used to create
an array of unique elements, and to check for the presence of elements in arrays.

Accordingly, they have been replaced in 2.0.8 with equivalent code that relies on standard built-in objects.

This PR has been submitted through the course of work for @opengovsg

🏁 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

[LoneRifle]

@mejo- not sure what happened with the Cypress 5 runner test, but it doesn't appear related to my PR:
https://github.com/nextcloud/text/actions/runs/8271282152/job/22630827977

[mejo-]

Thanks for the contribution @LoneRifle.

I manually checked that this PR does nothing more than npm update prosemirror-trailing-node.

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