Fix BODY_MIGHT_COMPLETE_NORMALLY_CATCH_ERROR lint (#3631)

diff --git a/lib/src/error_group.dart b/lib/src/error_group.dart
index cc1457f..11607bb 100644
--- a/lib/src/error_group.dart
+++ b/lib/src/error_group.dart
@@ -191,7 +191,15 @@
 
     // Make sure _completer.future doesn't automatically send errors to the
     // top-level.
-    _completer.future.catchError((_) {});
+    Future<void> swallowErrors(Future future) async {
+      try {
+        await future;
+      } catch (_) {
+        // Do nothing.
+      }
+    }
+
+    swallowErrors(_completer.future);
   }
 
   @override