[Bazel CI] ERROR: rules_rust_prost: implicit attribute defaults to @bazel_tools//tools/cpp:empty, fails single-file check (08-grpc-client-server)

[deepalak56]

CI: https://buildkite.com/bazel/bazel-at-head-plus-downstream/builds/5787#01a0eb5b-116d-49e9-a0e3-ef8d289bb8b9

Platform: Ubuntu, MacOs.

Logs:

(04:11:09) ERROR: /var/lib/buildkite-agent/builds/bk-docker-r9mr/bazel-org-repo-root/examples/rust-examples/08-grpc-client-server/proto_bindings/BUILD.bazel:6:14: in (an implicit dependency) attribute of @@rules_rust_prost+//private:prost.bzl%rust_prost_aspect aspect on proto_library rule //proto_bindings:proto_bindings: '@@bazel_tools//tools/cpp:empty' must produce a single file. Since this rule was created by the macro 'proto_library', the error might have been caused by the macro implementation
--
  | (04:11:09) ERROR: Analysis of target '//proto_bindings:proto_bindings' (config: 46994db) failed
  | (04:11:09) ERROR: Analysis of target '//grpc_server:demo_tests_tests/demo_tests_test' failed; build aborted: Analysis failed
  | (04:11:09) INFO: Elapsed time: 34.373s
  | (04:11:09) INFO: 0 processes.
  | (04:11:09) ERROR: Build did NOT complete successfully
  | (04:11:10) INFO: Streaming build results to: https://btx.cloud.google.com/invocations/7221e201-d224-499f-ac50-d5b48017d89d
  | bazel build failed with exit code 1
  | 🚨 Error: The command exited with status 1

Culprit: Commit 12b6ea57

Steps:

git clone https://github.com/bazelbuild/examples.git
git reset 45bfd9d --hard
export USE_BAZEL_VERSION=aadedf39b3cb71f95332d47c228b2432df144f35
bazel build --config=remote //...

CC Greenteam @SalmaSamy

[deepalak56]

Commit 12b6ea57 pointed @bazel_tools//tools/cpp:grep-includes at :empty, but rules_rust_prost (≤0.74.0) needs that label to give exactly one file, so the Rust gRPC example now fails with '@bazel_tools//tools/cpp:empty' must produce a single file. Should grep-includes point to a dummy target that has exactly one file (right now :empty has none), or upgrade the examples repo to a newer rules_rust_prost that doesn't need grep-includes, if there is one.
CC @meteorcloudy