Fixed Font Awesome CSS Pseudo-elements not rendering in v6.x

[alexandrevryghem]

Description

When Font Awesome was updated from v5.5.0 to v6.2.1 the CSS Pseudo-elements were not correctly updated this small PR fixes this issue. More information on this can be found here.

Instructions for Reviewers

Verify that the icons are now rendered correctly again

Guidance for how to test or review this PR:

• The easiest way to check this is by going to Edit Item > Relationships of a publication and click on + Add on the Authors (persons) & Organizational Units sections

Checklist

• [x] 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.
• [x] My PR passes ESLint validation using yarn lint
• [x] My PR doesn't introduce circular dependencies (verified via yarn check-circ-deps)
• [x] My PR includes TypeDoc comments for all new (or modified) public methods and classes. It also includes TypeDoc for large or complex private methods.
• [x] My PR passes all specs/tests and includes new/updated specs or tests based on the Code Testing Guide.
• [x] 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.
• [x] If my PR includes new features or configurations, I've provided basic technical documentation in the PR itself.
• [x] If my PR fixes an issue ticket, I've linked them together.