Update plugin_ffi generated file to match FFIgen 9.0.0 (#134614)

Template plugin_ffi uses FFIgen and generates both the FFIgen inputs and the generated file.

We rolled FFIgen to 9.0.0 in flutter/flutter#130494, which means a slight change to the generated file.

* https://github.com/dart-lang/ffigen/issues/619

Note, because of flutter/flutter#105695, we run the test on the FFIgen repo rather than on the flutter CI.

packages/flutter_tools/templates/plugin_ffi/lib/projectName_bindings_generated.dart.tmpl

@@ -5,6 +5,7 @@
 // AUTO GENERATED FILE, DO NOT EDIT.
 //
 // Generated by `package:ffigen`.
+// ignore_for_file: type=lint
 import 'dart:ffi' as ffi;
 
 /// Bindings for `src/{{projectName}}.h`.