fix(scrapy): Close AsyncThread on scheduler open() failure

If `open_rq()` raises, Scrapy will not call `close()`, so the
`AsyncThread` (and its event loop thread) would leak. Close it
explicitly before re-raising.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: vdusek

src/apify/scrapy/scheduler.py

@@ -61,6 +61,7 @@ async def open_rq() -> RequestQueue:
         try:
             self._rq = self._async_thread.run_coro(open_rq())
         except Exception:
+            self._async_thread.close()
             traceback.print_exc()
             raise