Install dependencies before trying to get machine info

[eddyashton]

#7851 just merged, but breaks the Bencher job: https://github.com/microsoft/CCF/actions/runs/25160593167/job/73753717210

++ awk '/^cpu family/{f=$NF} /^model\t/{m=$NF} /^stepping/{s=$NF; printf "%02x%02x%02x",f,m,s; exit}' /proc/cpuinfo
/__w/_temp/4be445c7-1a83-486c-9489-13c415051904.sh: line 6: awk: command not found
...
Error: Process completed with exit code 127.

If we install dependencies first, we should get awk from build-essential.

[Copilot]

Pull request overview

Fixes the Bencher GitHub Actions workflow failure introduced by #7851 by ensuring required tooling (eg awk) is installed before collecting machine metadata used to derive the Bencher testbed slug.

Changes:

• Move the ./scripts/setup-ci.sh dependency installation step to run before the shared “Machine info” step in bencher.yml.