Add exception protection for unexpected conditions during request handling

pr_agent/servers/github_polling.py

@@ -37,6 +37,7 @@ async def polling_loop():
         raise ValueError("User token must be set to get notifications")
     async with aiohttp.ClientSession() as session:
         while True:
+            try:
                 headers = {
                     "Accept": "application/vnd.github.v3+json",
                     "Authorization": f"Bearer {token}"
@@ -81,6 +82,9 @@ async def polling_loop():
                         print(f"Failed to fetch notifications. Status code: {response.status}")
 
                 await asyncio.sleep(5)
+            except Exception as e:
+                logging.error(f"Exception during processing of a notification: {e}")
+                await asyncio.sleep(5)
 
 if __name__ == '__main__':
     asyncio.run(polling_loop())