fix: build_runnerのバージョンを2.7.0から2.4.13にダウングレード

Author: LibraryLibrarian

pubspec.yaml

@@ -33,7 +33,7 @@ dev_dependencies:
   flutter_test:
     sdk: flutter
   flutter_lints: ^5.0.0
-  build_runner: ^2.7.0
+  build_runner: ^2.4.13
   json_serializable: 6.9.0
   file: ^7.0.1