[roll] Roll fuchsia [cast] Remove //src/cast and last reference to it

https://fxrev.dev/769058 was supposed to delete //src/cast, but this
METADATA file was added after that CL was created and not included in
the CL. Also remove an obsolete visibility reference.

Original-Bug: 105627, 42056877
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/967265
Owners-Override: James Robinson <jamesr@google.com>
Original-Revision: 40bffbeab63cec204968fb417094e11d8c8b1feb
GitOrigin-RevId: d80e8e18be2e6d27516138b4db5083973398c7cd
Change-Id: I0d89b4f8ef269eca61e0fe0c69413f53f567df8d
diff --git a/stem b/stem
index 79430c9..82c6b9e 100644
--- a/stem
+++ b/stem
@@ -11,7 +11,7 @@
              githooks="integration/git-hooks"
              remote="https://fuchsia.googlesource.com/fuchsia"
              gerrithost="https://fuchsia-review.googlesource.com"
-             revision="2a707f7ed038fbd40fe7397e3a6df5df34dcce8c"/>
+             revision="40bffbeab63cec204968fb417094e11d8c8b1feb"/>
   </projects>
   <hooks>
     <hook name="install-environment"