LibWeb: Implement UserActivation

Author: https://github.com/jamierocks
Commit: 01bd179eef
Pull-request: https://github.com/SerenityOS/serenity/pull/24437
Reviewed-by: https://github.com/ADKaster ✅
Reviewed-by: https://github.com/mattco98
Reviewed-by: https://github.com/tcl3

Userland/Libraries/LibWeb/HTML/UserActivation.idl

@@ -0,0 +1,6 @@
+// https://html.spec.whatwg.org/multipage/interaction.html#useractivation
+[Exposed=Window]
+interface UserActivation {
+    readonly attribute boolean hasBeenActive;
+    readonly attribute boolean isActive;
+};