Revert "Disable layering check for Objective-C (#29375)"

This reverts commit 14afb3a3ea6c650691a893b9bd7e844da5a6ee06.
diff --git a/src/objective-c/BUILD b/src/objective-c/BUILD
index f75edc8..a613c55 100644
--- a/src/objective-c/BUILD
+++ b/src/objective-c/BUILD
@@ -19,10 +19,7 @@
 
 licenses(["notice"])
 
-package(
-    default_visibility = ["//visibility:public"],
-    features = ["-layering_check"],
-)
+package(default_visibility = ["//visibility:public"])
 
 exports_files(["LICENSE"])