fix(transport): skip unix socket tests when local feature is enabled

The local feature causes ().serve(transport) to use spawn_local, which
requires a LocalSet. Gate the integration tests with not(feature = "local")
to match every other integration test in the repo.

Author: wpfleger96

crates/rmcp/tests/test_unix_socket_transport.rs

@@ -1,4 +1,8 @@
-#![cfg(all(unix, feature = "transport-streamable-http-client-unix-socket"))]
+#![cfg(all(
+    unix,
+    feature = "transport-streamable-http-client-unix-socket",
+    not(feature = "local")
+))]
 
 use std::{collections::HashMap, sync::Arc};