chore(ci): replace archived actions-rs/cargo with bare cargo invocations (#14017)

The actions-rs/ GitHub organization is archived and no longer
maintained. Its SHA-pinned references are still resolvable today, but
the org could be deleted or reclaimed at any point — at which moment
the pinned SHAs would become unreachable and every workflow that
references them would fail to start.

Replace the two actions-rs/cargo steps in reusable-rust-test.yml with
direct `cargo clippy` and `cargo fmt` invocations. The `rust_check`
job already installs the Rust toolchain via the local
./.github/actions/rustup composite (with `save-if: true, key: check`),
which provides clippy and rustfmt components — no additional toolchain
setup is required.

Behavior is unchanged: same cargo subcommand, same args.

  - Run Clippy:  cargo clippy --workspace --all-targets --tests -- -D warnings
  - Run rustfmt: cargo fmt --all -- --check

Author: stormslowly

.github/workflows/reusable-rust-test.yml

@@ -64,16 +64,10 @@ jobs:
         run: cargo workspaces exec cargo check --all-targets --locked
 
       - name: Run Clippy
-        uses: actions-rs/cargo@844f36862e911db73fe0815f00a4a2602c279505 # v1
-        with:
-          command: clippy
-          args: --workspace --all-targets --tests -- -D warnings
+        run: cargo clippy --workspace --all-targets --tests -- -D warnings
 
       - name: Run rustfmt
-        uses: actions-rs/cargo@844f36862e911db73fe0815f00a4a2602c279505 # v1
-        with:
-          command: fmt
-          args: --all -- --check
+        run: cargo fmt --all -- --check
 
       - name: Install taplo
         run: cargo install taplo-cli --locked