fix: mathjax footnotes moved to buckram

[arzola]

Buckram styles needs to be included in buckram in order to avoid chocking the SCSS parser and have this working on all of pb themes

[ho-man-chan]

LGTM

[sentry-io]

Suspect Issues

This pull request was deployed and Sentry observed the following issues:

• ‼️ ReferenceError: jQuery is not defined 761(app/themes/pressbooks-book/dist/scripts/book) View Issue
• ‼️ TypeError: jQuery is not a function 761(app/themes/pressbooks-book/dist/scripts/book) View Issue
• ‼️ SyntaxError: Failed to execute 'querySelector' on 'Document': '#4l2p2' is not a valid selector. Object.init(app/themes/pressbooks-book/dist/scr... View Issue
• ‼️ ReferenceError: jQuery is not defined Object.761(app/themes/pressbooks-book/dist/scri... View Issue
• ‼️ SyntaxError: The string did not match the expected pattern. init(app/themes/pressbooks-book/dist/scripts/book) View Issue

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