Custom callout icons are not displayed

[Yiming-M]

Describe the bug
I have some callout blocks defined using CSS but their icons are not shown in the slides.

Samples to Reproduce
Let's say there is a customized callout block defined in the following way:

.callout[data-callout="pros"] { --callout-color: 42, 157, 143; --callout-icon: "<svg aria-hidden=\"true\" focusable=\"false\" data-prefix=\"fas\" data-icon=\"thumbs-up\" class=\"svg-inline--fa fa-thumbs-up fa-w-16\" role=\"img\" xmlns=\"http://www.w3.org/2000/svg\" viewBox=\"0 0 512 512\"><path fill=\"currentColor\" d=\"M104 224H24c-13.255 0-24 10.745-24 24v240c0 13.255 10.745 24 24 24h80c13.255 0 24-10.745 24-24V248c0-13.255-10.745-24-24-24zM64 472c-13.255 0-24-10.745-24-24s10.745-24 24-24 24 10.745 24 24-10.745 24-24 24zM384 81.452c0 42.416-25.97 66.208-33.277 94.548h101.723c33.397 0 59.397 27.746 59.553 58.098.084 17.938-7.546 37.249-19.439 49.197l-.11.11c9.836 23.337 8.237 56.037-9.308 79.469 8.681 25.895-.069 57.704-16.382 74.757 4.298 17.598 2.244 32.575-6.148 44.632C440.202 511.587 389.616 512 346.839 512l-2.845-.001c-48.287-.017-87.806-17.598-119.56-31.725-15.957-7.099-36.821-15.887-52.651-16.178-6.54-.12-11.783-5.457-11.783-11.998v-213.77c0-3.2 1.282-6.271 3.558-8.521 39.614-39.144 56.648-80.587 89.117-113.111 14.804-14.832 20.188-37.236 25.393-58.902C282.515 39.293 291.817 0 312 0c24 0 72 8 72 81.452z\"></path></svg>"; }

Then use this block in Obsidian in the following way:

> [!pros] Pros
> Lorem ipsum dolor sit amet, consectetur adipiscing elit.

This is what's displayed in Obsidian editor:

But this is what I've got in the slides:

Expected behavior
In the slides, the callout block should look something similar to what's shown in Obsidian.