style: dart format (fixes CI 'Verify formatting' job)

The last CI run (May) failed only on the format check; two files were
unformatted — test/setup_cli_integration_test.dart (pre-existing) and
the new cancellation invariant test. `dart format --set-exit-if-changed`
now passes clean, clearing the one blocker that made ci.yml red.

Author: vietnguyentuan2019

test/setup_cli_integration_test.dart

@@ -6,8 +6,7 @@ void main() {
   // Absolute path to the CLI entrypoint. The tests run the CLI with
   // workingDirectory set to a temp mock project, so a relative 'bin/setup.dart'
   // would resolve against the temp dir and fail with "Could not find file".
-  final setupScript =
-      path.join(Directory.current.path, 'bin', 'setup.dart');
+  final setupScript = path.join(Directory.current.path, 'bin', 'setup.dart');
 
   late Directory tempDir;
   late File infoPlist;

test/unit/cancellation_rethrow_invariant_test.dart

@@ -83,7 +83,8 @@ void main() {
       });
     }
 
-    test('the invariant list matches the workers directory (no new worker '
+    test(
+        'the invariant list matches the workers directory (no new worker '
         'silently skips the check)', () {
       // Not every worker needs the rethrow — some have no local catch and
       // correctly rely on BaseKmpWorker, and WebSocketWorker uses try/finally.