Stop Ink Friendly snippet making text unselectable in output PDF

[G-Ambatte]

This PR resolves #3563.

This PR changes the Ink Friendly snippet to use box-shadow instead of filter. This should achieve the same visual effect while not rendering the output PDF as an image.

[dbolack-ab]

Is there a Brew we can compare before and after results with?

[G-Ambatte]

Is there a Brew we can compare before and after results with?

Example 1: Current
HB link: https://homebrewery.naturalcrit.com/share/wjdLwCIMiGf7
PDF: Ink Friendly Example 1_ Current - The Homebrewery.pdf

Example 2: PR Changes
HB link: https://homebrewery.naturalcrit.com/share/oU5XmiPzlhMg
PDF: Ink Friendly Example 2_ Proposed - The Homebrewery.pdf

You should see that the "current" brew contains only a single framed monster block and the Ink Friendly snippet. However, the PDF output is that of an image; the text is not able to be selected or interacted with.
However, you should also see that the PR changes contains the exact same framed monster block, and the only difference is in the style, where the Ink Friendly snippet has been replaced with the version from this PR. The resultant PDF has text that can be highlighted and interacted with as expected for text.