* Fix outstanding UX issues with replies/mentions/keyword notifs
* Use createRoot instead of deprecated ReactDOM.render
I foresee this change being made across the codebase shortly
and want to proactively prevent my PR from falling behind
* Clean up react root on unmount
* Remove addition of left-edge highlight on message mentions
It is clear that it would be best for me to address
this piece in a separate PR.
* Update call to ReactRootManager.render
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Co-authored-by: Michael Telatynski <7t3chguy@gmail.com>