fix(managed-agents): use is_none_or in barrier readiness test

Replace map_or(true, ...) with is_none_or(...) per clippy lint
unnecessary_map_or (-D warnings gate).

Co-authored-by: Will Pfleger <pfleger.will@gmail.com>
Signed-off-by: Will Pfleger <pfleger.will@gmail.com>

desktop/src-tauri/src/managed_agents/persona_events/tests.rs

@@ -1024,7 +1024,7 @@ mod flush_barrier {
         {
             let guard = state.config_sync_ready_scope.lock().unwrap();
             assert!(
-                guard.as_ref().map_or(true, |p| *p != db_path),
+                guard.as_ref().is_none_or(|p| *p != db_path),
                 "scope is not ready after a barrier failure — flush must skip"
             );
         }