Fix Engine::same().

Preferably we'd be able to compare two trait objects both vptr and struct, but rust doesn't have a way to do that without relying on unsafe code.

Fixes error with `cargo clippy`.

lib/api/src/store.rs

@@ -21,7 +21,7 @@ impl Store {
     }
 
     pub fn same(a: &Store, b: &Store) -> bool {
-        Arc::ptr_eq(&a.engine, &b.engine)
+        a.engine.uuid() == b.engine.uuid()
     }
 }