fix NEXUS-703: try to fix event loop in separate thread

Author: pawel-kmiecik

src/unstructured_client/_hooks/custom/split_pdf_hook.py

@@ -63,12 +63,13 @@ def _get_asyncio_loop() -> asyncio.AbstractEventLoop:
             loop = asyncio.get_event_loop()
         except RuntimeError:
             loop = asyncio.new_event_loop()
+            asyncio.set_event_loop(loop)
     else:
         try:
             loop = asyncio.get_running_loop()
         except RuntimeError:
             loop = asyncio.new_event_loop()
-    asyncio.set_event_loop(loop)
+            asyncio.set_event_loop(loop)
     return loop
 
 def _run_coroutines_in_separate_thread(