LibWeb: Don't strip leading '?' in query initializing a URL

In our implementation of url-initialize, we were invoking the
constructor of URLSearchParams:

https://url.spec.whatwg.org/#dom-urlsearchparams-urlsearchparams

Instead of the 'initialize' AO:

https://url.spec.whatwg.org/#urlsearchparams-initialize

This has the small difference of stripping any leading '?' from the
query (which we are not meant to be doing!).

Tests/LibWeb/Text/input/URL/url.html

@@ -36,6 +36,7 @@
             { input: '  \t', base: 'http://ladybird.org/foo/bar' },
             { input: '/c:/foo/bar', base: 'file:///c:/baz/qux' },
             { input: '', base: 'file:///test?test#test' },
+            { input: '??a=b&c=d', base: 'http://example.org/foo/bar' },
         ];
 
         for (url of urls) {