[roll] Roll fuchsia [build][bazel][rust] Add tinyjson crate.

See OSRB approval at https://fxbug.dev/114067

The tinyjson crate is an implicit dependency of the @rules_rust
repository. This CL adds its to our third_party crates, and modifies
the template.WORKSPACE.bazel file to create a local override.

Doing this allows building Rust binaries with download restrictions
enabled. To test it:

  fx build bazel_workspace
  fx bazel build //src/lib/zircon/rust:*

Which previously failed with an error complaining about the download.

Original-Bug: 112781
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/753382
Original-Revision: 449f8979db0cd676c0394e2b4eb19ea8904ce269
GitOrigin-RevId: 27597291d77095c64f78a01201694d5c7e9edf69
Change-Id: I13f0d54f4504fe3d77870fe044a510858bada0a5
diff --git a/stem b/stem
index 02a8f55..4ce85b7 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="94c03c87d90471e50df964eec512ad1180600cad"/>
+             revision="449f8979db0cd676c0394e2b4eb19ea8904ce269"/>
   </projects>
   <hooks>
     <hook name="install-environment"