[9.16] fix: test: refresh base image repos before installing from them

Stale repositories cause issue on installation in the `docs:pdf` CI job:

    E: Failed to fetch http://deb.debian.org/debian/pool/main/s/systemd/libsystemd-shared_252.22-1%7edeb12u1_amd64.deb  404  Not Found [IP: 2a04:4e42:78::644 80]
    E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?

Validation job: https://gitlab.isc.org/isc-projects/bind9/-/jobs/4487570

Backport of MR !9164

Merge branch 'mnowak/refresh-base-image-repo-before-installation' into 'bind-9.16'

See merge request isc-projects/bind9!9129