Mark objc_compilation_support as publicly visible

Copybara Import from #568

BEGIN_PUBLIC
Mark `objc_compilation_support` as publicly visible (#568)

We need this to support Bazel 9+ (see: bazelbuild/rules_apple#2862)

Closes #568
END_PUBLIC

COPYBARA_INTEGRATE_REVIEW=#568 from luispadron:patch-1 c6b6874
PiperOrigin-RevId: 857993845
Change-Id: I5dc48c54416d5c185627067be7cf8d61354d5343

Author: luispadron

cc/private/rules_impl/BUILD

@@ -106,10 +106,7 @@ bzl_library(
 bzl_library(
     name = "objc_compilation_support_bzl",
     srcs = ["objc_compilation_support.bzl"],
-    visibility = [
-        "//cc:__subpackages__",
-        "//third_party/bazel_rules/rules_apple/apple:__subpackages__",
-    ],
+    visibility = ["//visibility:public"],
     deps = [
         ":objc_common",
         "//cc/common:cc_helper_bzl",