[ios][fuzzer] Fix visibility after changes to iOS build rules

The internal targets used to implement the ios_app_bundle template
have changed with https://crrev.com/c/4345535, update the visibility
to reflect the new list of targets that are allowed to depend on the
private fuzzer targets.

Fixes https://ci.chromium.org/p/chromium/builders/ci/Libfuzzer%20Upload%20iOS%20Catalyst%20Debug

Bug: 1337780
Change-Id: Ib69effffbbc2cb71a061035d2bf27ad83fd716ea
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4349935
Owners-Override: Sam Zackrisson <saza@google.com>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Sam Zackrisson <saza@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1118701}