fix: remove stale pragma no cover from send_roots_list_changed

This line is now covered by the E2E tenant notification test.

Author: andylim-duo

src/mcp/client/session.py

@@ -407,7 +407,7 @@ async def list_tools(self, *, params: types.PaginatedRequestParams | None = None
 
         return result
 
-    async def send_roots_list_changed(self) -> None:  # pragma: no cover
+    async def send_roots_list_changed(self) -> None:
         """Send a roots/list_changed notification."""
         await self.send_notification(types.RootsListChangedNotification())