LibWeb: Add IDL definition for SVGScriptElement

It does not currently handle any of the actual scripting, but this
should at least allow us to create an instance of the element.

The test being added here isn't actually testing much, but before the
previous commit we used to crash parsing the page due to a TODO().

Userland/Libraries/LibWeb/SVG/SVGScriptElement.h

@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2023, Shannon Booth <shannon@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibWeb/SVG/SVGElement.h>
+
+namespace Web::SVG {
+
+// https://www.w3.org/TR/SVG/interact.html#InterfaceSVGScriptElement
+class SVGScriptElement : public SVGElement {
+    WEB_PLATFORM_OBJECT(SVGScriptElement, SVGElement);
+
+public:
+protected:
+    SVGScriptElement(DOM::Document&, DOM::QualifiedName);
+
+    virtual void initialize(JS::Realm&) override;
+
+private:
+    virtual bool is_svg_script_element() const final { return true; }
+};
+
+}
+
+namespace Web::DOM {
+
+template<>
+inline bool Node::fast_is<SVG::SVGScriptElement>() const { return is_svg_script_element(); }
+
+}