Issue #3353096 by Spokje: [random test failure] Try to un-skip and fix InlineBlockPrivateFilesTest::testPrivateFiles() in context of [#3353085]

core/modules/layout_builder/tests/src/FunctionalJavascript/InlineBlockPrivateFilesTest.php

@@ -63,7 +63,6 @@ class InlineBlockPrivateFilesTest extends InlineBlockTestBase {
    */
   public function testPrivateFiles() {
     // Skipped due to frequent random test failures.
-    $this->markTestSkipped();
     $assert_session = $this->assertSession();
     LayoutBuilderEntityViewDisplay::load('node.bundle_with_section_field.default')
       ->enableLayoutBuilder()