Unset the top-level module fetch flag in dynamic imports

The the top-level module fetch is only used in two steps of "fetch a
single module script":
- Step 9, where it only has effect if  descrination is "worker",
  "sharedworker" or "serviceworker" (but for dynamic imports it's always
  "script")
- Step 11, where it only has effect if there are custom "perform the
  fetch" steps, but "fetch an import() module script graph" is never
  called with custom "perform the fetch" steps.

Author: nicolo-ribaudo

source

@@ -95855,10 +95855,11 @@ document.querySelector("button").addEventListener("click", bound);
   sequence</span> containing the response body. <dfn export for="fetching scripts"><var
   data-x="fetching-scripts-is-top-level">isTopLevel</var></dfn> will be true for all <span>classic
   script</span> fetches, and for the initial fetch when <span data-x="fetch an external module
-  script graph">fetching an external module script graph</span>, <span data-x="fetch a module worker
-  script graph">fetching a module worker script graph</span>, or <span data-x="fetch an import()
-  module script graph">fetching an import() module script graph</span>, but false for the fetches
-  resulting from <code data-x="">import</code> statements encountered throughout the graph.</p>
+  script graph">fetching an external module script graph</span>, or <span data-x="fetch a module
+  worker script graph">fetching a module worker script graph</span>, but false for the fetches
+  resulting from <code data-x="">import</code> statements encountered throughout the graph or from
+  <span data-x="fetch an import() module script graph">fetching an import() module script
+  graph</span>.</p>
 
   <p>By default, not supplying a <span data-x="fetching-scripts-perform-fetch">perform the fetch
   hook</span> will cause the below algorithms to simply <span data-x="concept-fetch">fetch</span>
@@ -96182,7 +96183,7 @@ document.querySelector("button").addEventListener("click", bound);
    <li>
     <p><span>Fetch a single module script</span> given <var>url</var>, <var>settings
     object</var>, "<code data-x="">script</code>", <var>options</var>, <var>settings object</var>,
-    "<code data-x="">client</code>", <var>moduleRequest</var>, true, and with the following steps
+    "<code data-x="">client</code>", <var>moduleRequest</var>, false, and with the following steps
     given <var>result</var>:</p>
 
     <ol>