ci: install the runner's own packages through the mirror fallback too (#10831)

The e2e job overwrote the runner's sources.list with two azure-only lines and
installed fuse from it, so the same mirror outage that took out the image
builds failed the step outright - this time on the runner rather than inside
the container, where the image-side fallback cannot reach.

Install through the same helper, and widen its rewrite to match any archive
host so it works whether the pristine list came from the base image
(archive.ubuntu.com) or from a CI runner (azure.archive.ubuntu.com). Keeping
the runner's original list also restores the security and backports pockets,
which the hand-written two-line replacement dropped.

Verified against the outage itself: with the pristine list pointed at Azure,
the build logged the skip after Azure timed out for real and installed from
archive.ubuntu.com.

docker/apt-install

@@ -8,7 +8,9 @@ set -e
 [ -f /etc/apt/sources.list.orig ] || cp /etc/apt/sources.list /etc/apt/sources.list.orig
 
 for mirror in azure.archive.ubuntu.com archive.ubuntu.com; do
-	sed "s|http://archive\.ubuntu\.com/ubuntu|http://$mirror/ubuntu|g; s|http://security\.ubuntu\.com/ubuntu|http://$mirror/ubuntu|g" \
+	# Any archive host, so this works whether the pristine list came from the
+	# base image (archive.ubuntu.com) or a CI runner (azure.archive.ubuntu.com).
+	sed "s|http://[a-z0-9.]*archive\.ubuntu\.com/ubuntu|http://$mirror/ubuntu|g; s|http://security\.ubuntu\.com/ubuntu|http://$mirror/ubuntu|g" \
 		/etc/apt/sources.list.orig > /etc/apt/sources.list
 	if apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=15 update && \
 		DEBIAN_FRONTEND=noninteractive apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=15 install -y \