Fix recently introduced crash in wxFileSystem::OpenFile()

Fix the code after the changes of the recent b03850e367 (Reduce manual
memory management in wxFileSystemHandler code, 2026-07-20) which wrongly
destroyed the smart pointer too early.

src/common/filesys.cpp

@@ -295,7 +295,7 @@ wxFSFile* wxLocalFSHandler::OpenFile(wxFileSystem& WXUNUSED(fs), const wxString&
     if ( !is->IsOk() )
         return nullptr;
 
-    return new wxFSFile(is.get(),
+    return new wxFSFile(is.release(),
                         location,
                         wxEmptyString,
                         GetAnchor(location)