FSEngine: Fix engine to handle root path correctly

Change-Id: Idd5b75875a87e624675ed40cba668caf5013e6a9
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/libs/utils/fsengine/fsenginehandler.cpp

@@ -52,10 +52,10 @@ QAbstractFileEngine *FSEngineHandler::create(const QString &fileName) const
         FilePath filePath = FilePath::fromString(fixedFileName);
         if (filePath.needsDevice())
             return new FSEngineImpl(filePath);
+    }
 
     if (fixedFileName.compare(QDir::rootPath(), Qt::CaseInsensitive) == 0)
         return new RootInjectFSEngine(fixedFileName);
-    }
 
     return nullptr;
 }