test: convert test_integration.py to in-memory transport (fix flaky) (#2277)

Author: maxisbey

src/mcp/server/session.py

@@ -474,7 +474,7 @@ async def send_progress_notification(
             related_request_id,
         )
 
-    async def send_resource_list_changed(self) -> None:  # pragma: no cover
+    async def send_resource_list_changed(self) -> None:
         """Send a resource list changed notification."""
         await self.send_notification(types.ResourceListChangedNotification())