[codex] Use git CLI for Cargo fetches across Rust workflows

[anp-oai]

Why

Cargo's libgit2 transport has intermittently failed while fetching git dependencies with nested submodules. #25644 applied CARGO_NET_GIT_FETCH_WITH_CLI=true to the main Rust release build after macOS SecureTransport/libgit2 failures while cloning libwebrtc's nested libyuv submodule. Similar flakes can affect other Cargo-bearing Rust jobs.

What changed

Configure CARGO_NET_GIT_FETCH_WITH_CLI=true at workflow scope for the remaining Cargo-bearing Rust workflows:

• fast Rust CI and cargo-deny
• reusable Windows and argument-comment-lint release workflows
• rusty-v8-release and v8-canary Cargo builds and smoke tests

The full Rust CI, reusable nextest workflow, and primary Rust release build already had the override. Bazel-only workflows are unchanged because they use a different dependency fetch path.

Validation

• Parsed all .github/workflows/*.yml files as YAML.
• Scanned Cargo-bearing workflows to confirm they configure CARGO_NET_GIT_FETCH_WITH_CLI.