Ladybird: Use Browser's CookieJar.{cpp,h}

There are no custom changes for Ladybird in the current copies of those
files, so we just need to ensure to keep Ladybird up to date for any
changes made upstream.

This fixes a build issue introduced by https://github.com/SerenityOS/serenity/pull/15736.

Ladybird/WebContentView.cpp

@@ -8,7 +8,6 @@
 
 #include "WebContentView.h"
 #include "ConsoleWidget.h"
-#include "CookieJar.h"
 #include "ModelTranslator.h"
 #include "Utilities.h"
 #include <AK/Assertions.h>
@@ -19,6 +18,7 @@
 #include <AK/NonnullOwnPtr.h>
 #include <AK/StringBuilder.h>
 #include <AK/Types.h>
+#include <Browser/CookieJar.h>
 #include <Kernel/API/KeyCode.h>
 #include <LibCore/ArgsParser.h>
 #include <LibCore/EventLoop.h>