Enable the unicorn/prefer-dom-node-append ESLint plugin rule

This rule will help enforce slightly shorter code, especially since you can insert multiple elements at once, and according to MDN `Element.append()` is available in all browsers that we currently support.

Please find additional information here:
 - https://developer.mozilla.org/en-US/docs/Web/API/Element/append
 - https://github.com/sindresorhus/eslint-plugin-unicorn/blob/main/docs/rules/prefer-dom-node-append.md

src/display/display_utils.js

@@ -459,7 +459,7 @@ function loadScript(src, removeScriptElement = false) {
     script.onerror = function () {
       reject(new Error(`Cannot load script at: ${script.src}`));
     };
-    (document.head || document.documentElement).appendChild(script);
+    (document.head || document.documentElement).append(script);
   });
 }