[flutter_markdown] remove a test about preserving HTML entities (#2757)

diff --git a/packages/flutter_markdown/test/html_test.dart b/packages/flutter_markdown/test/html_test.dart
index 11525d5..0d3a386 100644
--- a/packages/flutter_markdown/test/html_test.dart
+++ b/packages/flutter_markdown/test/html_test.dart
@@ -51,18 +51,5 @@
         expectTextStrings(tester.allWidgets, <String>['<']);
       },
     );
-
-    testWidgets(
-      "doesn't convert existing HTML entities when parsing",
-      (WidgetTester tester) async {
-        await tester.pumpWidget(
-          boilerplate(
-            const Markdown(data: '&amp; &copy; &#60; &#x0007B;'),
-          ),
-        );
-        expectTextStrings(
-            tester.allWidgets, <String>['&amp; &copy; &#60; &#x0007B;']);
-      },
-    );
   });
 }