Roll package:dds to 1.5.1 and add isCompleted guards around completers in base/dds.dart (#70712)

diff --git a/packages/flutter_tools/test/general.shard/resident_runner_test.dart b/packages/flutter_tools/test/general.shard/resident_runner_test.dart
index 2b824df..c8e66ee 100644
--- a/packages/flutter_tools/test/general.shard/resident_runner_test.dart
+++ b/packages/flutter_tools/test/general.shard/resident_runner_test.dart
@@ -57,6 +57,7 @@
   runnable: true,
   startTime: 0,
   isSystemIsolate: false,
+  isolateFlags: <vm_service.IsolateFlag>[],
 );
 
 final vm_service.Isolate fakePausedIsolate = vm_service.Isolate(
@@ -85,6 +86,7 @@
   runnable: true,
   startTime: 0,
   isSystemIsolate: false,
+  isolateFlags: <vm_service.IsolateFlag>[],
 );
 
 final vm_service.VM fakeVM = vm_service.VM(