Handle thrown maps and rejects from fe server (#37743)

packages/flutter_tools/lib/src/vmservice.dart

diff --git a/packages/flutter_tools/lib/src/vmservice.dart b/packages/flutter_tools/lib/src/vmservice.dart
index 777323c..b55f4da 100644
--- a/packages/flutter_tools/lib/src/vmservice.dart
+++ b/packages/flutter_tools/lib/src/vmservice.dart
@@ -1177,7 +1177,7 @@
       final Map<String, dynamic> response = await invokeRpcRaw('_reloadSources', params: arguments);
       return response;
     } on rpc.RpcException catch (e) {
-      return Future<Map<String, dynamic>>.error(<String, dynamic>{
+      return Future<Map<String, dynamic>>.value(<String, dynamic>{
         'code': e.code,
         'message': e.message,
         'data': e.data,