fix(system-upgrades): Workaround potential script failures

Currently various scriptlets fail as part of `dnf upgrade -y` due to
SELinux transitions conflicting with `spc_t`. Which also prevented a
proper kernel update.

Therefore this solution just triggers the right systemd job, that should
take care of the update, before checking if we need to reboot the
machine.

References:
https://danwalsh.livejournal.com/74754.html

infrastructure/system-upgrades/fedora.yaml

@@ -10,8 +10,9 @@ stringData:
     #!/bin/sh
     set -e
     set -x
-    dnf install -y dnf-utils
-    dnf upgrade -y --best
+    dnf install -y dnf-automatic
+    systemctl enable --now dnf-automatic.timer
+    systemctl start --wait dnf-automatic-install.service
     if ! dnf needs-restarting --reboothint; then
       systemctl reboot
     fi