ci: github: Harden the test workflow by using runner temp dir

This issue was reported by CodeQL, IMHOI the alert was over reacting
because contents was already extracted in a separate directory (which
is absent in tree, so there is no risk to override)

An extra check would be to verify a signed asset (using GPG),
along a ZWA public key shared in tree.

Potential fix for code scanning alert no. 1: Artifact poisoning

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>
Relate-to: Z-Wave-Alliance/OSWG#48 (comment)
Signed-off-by: Philippe Coval <philippe.coval@silabs.com>

Author: rzr

.github/workflows/test.yml

@@ -59,9 +59,9 @@ jobs:
           ${{ env.debian_packages }}
           && sudo apt-get clean -y
           && echo "https://github.com/Z-Wave-Alliance/z-wave-stack/issues/733"
-          && mkdir -p z-wave-stack-binaries
+          && mkdir -p ${{ runner.temp }}/z-wave-stack-binaries
           && tar xfz z-wave-stack-binaries-*-Linux.tar.gz
-          -C z-wave-stack-binaries
+          -C ${{ runner.temp }}/z-wave-stack-binaries
           && rm z-wave-stack-binaries-*-Linux.tar.gz
           && date -u
 
@@ -74,7 +74,7 @@ jobs:
           $ZPC_COMMAND --version
           docker-compose pull
           export ZPC_COMMAND="docker-compose up --abort-on-container-exit"
-          cd z-wave-stack-binaries/bin && file -E *_x86_REALTIME.elf && cd -
+          export z_wave_stack_binaries_bin_dir="${{ runner.temp }}/z-wave-stack-binaries/bin"         
           export ZPC_ARGS="--log.level=d"
           ./scripts/tests/z-wave-stack-binaries-test.sh
         continue-on-error: true