✅ Fix download stream tests (#2140)

The GitHub runner is much faster than our configurations, apparently.

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- [x] I have read the
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- [ ] I have added the required tests to prove the fix/feature I'm
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dio_test/lib/src/test/download_stream_tests.dart

@@ -49,13 +49,13 @@ void downloadStreamTests(
     test('cancels request', () async {
       final cancelToken = CancelToken();
 
-      Future.delayed(const Duration(milliseconds: 50), () {
+      Future.delayed(const Duration(milliseconds: 10), () {
         cancelToken.cancel();
       });
 
       await expectLater(
         dio.get(
-          '/bytes/5000',
+          '/bytes/10000',
           options: Options(responseType: ResponseType.stream),
           cancelToken: cancelToken,
         ),