clan-cli: Fix incorrect throw on clan update

pkgs/clan-cli/clan_cli/async_run.py

@@ -252,6 +252,7 @@ class AsyncRuntime:
             if task.finished and task.async_opts.check:
                 assert task.result is not None
                 error = task.result.error
+                if error is not None:
                     if log.isEnabledFor(logging.DEBUG):
                         log.error(
                             f"failed with error: {error}",
@@ -260,7 +261,8 @@ class AsyncRuntime:
                         )
                     else:
                         log.error(
-                        f"failed with error: {error}", extra={"command_prefix": name}
+                            f"failed with error: {error}",
+                            extra={"command_prefix": name},
                         )
                     err_count += 1