[WIP] Fix various bugs related to ep_mathjax

[Copilot]

Thanks for asking me to work on this. I will get started on it and keep this PR's description up to date as I form a plan and make progress.

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This section details on the original issue you should resolve

<issue_title>Various bugs</issue_title>
<issue_description>TODO: ep_mathjax can't be inserted on line that has ep_align
TODO: ep_mathjax looks weird in timeslider
TODO: ep_mathjax can't export to word doc

</issue_description>

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