LibWeb: Fire a pointer event on synthetic clicks

Author: https://github.com/shannonbooth
Commit: db0519ddc1
Pull-request: https://github.com/SerenityOS/serenity/pull/23886
Reviewed-by: https://github.com/kennethmyhra ✅

Tests/LibWeb/Text/input/HTML/HTMLElement-click.html

@@ -0,0 +1,15 @@
+<script src="../include.js"></script>
+<button id="myButton"></button>
+<script>
+    asyncTest(done => {
+        function handleClick(event) {
+            println(`Event: ${event.constructor.name}`);
+            done();
+        }
+
+        let button = document.getElementById("myButton");
+
+        button.addEventListener("click", handleClick);
+        button.click();
+    });
+</script>