add package_name for consistency across all platforms (#88457)

packages/flutter_tools/lib/src/project.dart

@@ -354,6 +354,7 @@ class FlutterProject {
         'version': buildName,
       if (buildNumber != null)
         'build_number': buildNumber,
+      'package_name': manifest.appName,
     };
     return jsonEncode(versionFileJson);
   }

packages/flutter_tools/test/general.shard/project_test.dart

@@ -288,6 +288,7 @@ void main() {
         expect(versionInfo['app_name'],'test');
         expect(versionInfo['version'],'1.0.0');
         expect(versionInfo['build_number'],'3');
+        expect(versionInfo['package_name'],'test');
       });
     });