Fixed MathJax code being displayed twice by dsMarkdown pipe

[alexandrevryghem]

References

• Fixes Mathjax code is displayed twice in the UI #2170
• Maintenance PR [Port dspace-7_x] Fixed MathJax code being displayed twice by dsMarkdown pipe #2392

Description

Fixed MathJax code being displayed twice, this is because a HTML tag mjx-assistive-mml is created for screen readers to be able to read the MathJax code. Because the dsMarkdown pipe sanitises the HTML it transformed this hidden HTML tag to text instead leading to the MathJax code being displayed twice.

Instructions for Reviewers

List of changes in this PR:

• Added the mjx-assistive-mml HTML tag (and it's child HTML tags) to the sanitizeHtml's allowedTags to ensure it won't be turned into text

Guidance for how to test/review this PR:

• Create a new item with the following content in dc.description.abstract:

  Lorem ipsum dolor sit amet, consectetur adipiscing elit. Aliquam rutrum mi ligula, eget luctus diam ultricies vitae ${\ell}$. Quisque elit libero, eleifend eu pretium a, gravida at felis. Proin sed imperdiet nibh. Integer sit amet eleifend ligula. Maecenas semper vestibulum lorem. Mauris ut tortor diam ${\color{Red}2\ell\geq\binom{d}{\lfloor\frac{d}{2} \rfloor}}$. Sed elementum erat dolor, id rhoncus augue dignissim et. Curabitur a ligula vestibulum sapien maximus ultricies dignissim at leo ${\color{Red}\textit{L}_T}$. Mauris vulputate magna at turpis eleifend, sit amet lacinia tellus malesuada. Nam nisi ex, ultrices sed posuere at, laoreet vel ligula. Aenean scelerisque in lacus sed tristique ${\color{Red}\mathcal{O}\left(\textit{L}_T\text{ log}\left(\textit{L}_T\ell \right) \right)}$. Pellentesque rhoncus viverra metus vitae scelerisque. Aliquam iaculis commodo erat, tincidunt auctor augue tincidunt sit amet. Suspendisse placerat velit ut magna vulputate semper. Praesent non aliquet tortor.
  

• Check that the MathJax code is only displayed once

Checklist

• My PR is small in size (e.g. less than 1,000 lines of code, not including comments & specs/tests), or I have provided reasons as to why that's not possible.
• My PR passes ESLint validation using yarn lint
• My PR doesn't introduce circular dependencies (verified via yarn check-circ-deps)
• My PR includes TypeDoc comments for all new (or modified) public methods and classes. It also includes TypeDoc for large or complex private methods.
• My PR passes all specs/tests and includes new/updated specs or tests based on the Code Testing Guide.
• If my PR includes new libraries/dependencies (in package.json), I've made sure their licenses align with the DSpace BSD License based on the Licensing of Contributions documentation.
• If my PR includes new features or configurations, I've provided basic technical documentation in the PR itself.
• If my PR fixes an issue ticket, I've linked them together.

[tdonohue]

👍 Thanks @alexandrevryghem ! Tested this locally and verified it fixes the bug. Code looks good too