Disable layering check for Objective-C (#29446)

These targets are currently not layering check clean.  Disabling it
ensures that they will continue to build even when we enable layering
check for Objective-C internally.

src/objective-c/BUILD

@@ -19,7 +19,10 @@ load("@build_bazel_rules_apple//apple:resources.bzl", "apple_resource_bundle")
 
 licenses(["notice"])
 
-package(default_visibility = ["//visibility:public"])
+package(
+    default_visibility = ["//visibility:public"],
+    features = ["-layering_check"],
+)
 
 exports_files(["LICENSE"])