[objective_c] Fix build hook (#2825)

Author: dcharkes

pkgs/objective_c/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 9.2.0+1
+
+- Fix [bug](https://github.com/dart-lang/native/issues/2824) where the build
+  hook was trying to access the code config if it was not provided.
+
 ## 9.2.0
 
 - Migrate to from a Flutter plugin to native assets. This enables

pkgs/objective_c/hook/build.dart

@@ -27,6 +27,11 @@ final logger = Logger('')
 
 void main(List<String> args) async {
   await build(args, (input, output) async {
+    if (!input.config.buildCodeAssets) {
+      // Don't build any other asset types.
+      return;
+    }
+
     const supportedOSs = {OS.iOS, OS.macOS};
     final os = input.config.code.targetOS;
     if (!supportedOSs.contains(os)) {

pkgs/objective_c/pubspec.yaml

@@ -4,7 +4,7 @@
 
 name: objective_c
 description: 'A library to access Objective C from Flutter that acts as a support library for package:ffigen.'
-version: 9.2.0
+version: 9.2.0+1
 repository: https://github.com/dart-lang/native/tree/main/pkgs/objective_c
 issue_tracker: https://github.com/dart-lang/native/issues?q=is%3Aissue+is%3Aopen+label%3Apackage%3Aobjective_c