[roll] Roll fuchsia [fidlc] Sometimes we have no ordinals on a method

Due to previous compilation errors, we might not have an ordinal on a
method, and must therefore protect the access.

Implementing the restriction on `fuchsia.io` requiring explicit ordinals
as a compiler check, rather than an assert. This avoids the compiler
failing in a more obscure way, and is more in line with how fidlc is
meant to operate.

Original-Bug: 77623
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/582341
Original-Revision: b7866d4c61e705d49589b6b06556ea011a3789d8
GitOrigin-RevId: c46d724d44ff8be9006f93fbc9cc49a376227407
Change-Id: I84da4b3e904770522b7e01f12590686df84cdc55
diff --git a/stem b/stem
index 948d2ee..7ca038e 100644
--- a/stem
+++ b/stem
@@ -10,7 +10,7 @@
              githooks=""
              remote="https://fuchsia.googlesource.com/fuchsia"
              gerrithost="https://fuchsia-review.googlesource.com"
-             revision="775a9e86b4c202f5bd9364dad1e3a55789f41d16"/>
+             revision="b7866d4c61e705d49589b6b06556ea011a3789d8"/>
   </projects>
   <hooks>
     <hook name="install-environment"