LibWeb: Implement HTMLImageElement.crossOrigin

Author: https://github.com/jamierocks
Commit: 2ffda00347
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/24
Reviewed-by: https://github.com/tcl3 ✅

Tests/LibWeb/Text/input/HTML/crossOrigin-attribute.html

@@ -2,7 +2,7 @@
 <script src="../include.js"></script>
 <script>
     test(() => {
-        for (let elementName of ["audio", "script", "video", "link"]) {
+        for (let elementName of ["audio", "script", "video", "link", "img"]) {
           const element = document.createElement(elementName);
           println(`${elementName} crossOrigin initial value: ${element.crossOrigin}`);
           element.crossOrigin = "invalid";