[latent_see] Add a visibility control for this library (#37898)

We'll want to annotate some internal systems with it going forward.

Closes #37898

COPYBARA_INTEGRATE_REVIEW=https://github.com/grpc/grpc/pull/37898 from ctiller:latent-vis 12e3e73c3c
PiperOrigin-RevId: 684948162

bazel/grpc_build_system.bzl

@@ -123,6 +123,7 @@ def _update_visibility(visibility):
         "iomgr_internal_errqueue": PRIVATE,
         "iomgr_buffer_list": PRIVATE,
         "json_reader_legacy": PRIVATE,
+        "latent_see": PRIVATE,
         "otel_plugin": PRIVATE,
         "public": PUBLIC,
         "ref_counted_ptr": PRIVATE,

src/core/BUILD

@@ -148,6 +148,7 @@ grpc_cc_library(
         "absl/strings",
         "absl/types:optional",
     ],
+    visibility = ["@grpc:latent_see"],
     deps = [
         "per_cpu",
         "ring_buffer",