Override systemd-journald with `ForwardToSyslog=no` to avoid disk exhaustion issues

[kot0dama]

Bug Description

The k8s snap defaults to trace log level, while the Ubuntu system defaults to ForwardToSyslog=yes.
This is a high of disk exhaustion risk on any k8s charm deployment.

I believe the charm should enforce ForwardToSyslog=no until at least one of these bugs is resolved with a remediation:
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/2147513
canonical/k8sd#31

Thank you!

To Reproduce

Deploy the charm and enable many workloads, watch syslog fill with kube api server trace level logs up to GBs instead of usual KBs.

Environment

Juju: 3.6.9

App                         Version  Status  Scale  Charm                       Channel        Rev  Exposed  Message
cinder-csi                  v1.27.1  active      1  cinder-csi                  1.33/stable     38  no       Versions: cinder-csi-driver=v1.27.1
easyrsa                     v3.0.9   active      1  easyrsa                     1.33/stable     74  no       Certificate Authority connected.
etcd                        3.4.37   active      3  etcd                        1.33/stable    788  no       Healthy with 3 known peers
grafana-agent                        active     10  grafana-agent               1/stable       489  no       tracing: off
k8s-control                 1.32.6   active      3  k8s                         1.32/stable    987  yes      Ready
k8s-worker                  1.32.6   active      3  k8s-worker                  1.32/stable    987  yes      Ready
landscape-client                     active     10  landscape-client            latest/edge     72  no       Client registered!
openstack-cloud-controller  v1.30.0  active      1  openstack-cloud-controller  1.33/stable     40  no       Versions: openstack-cloud-controller-manager=v1.30.0
openstack-integrator        yoga     active      1  openstack-integrator        1.33/stable    115  no       Ready
ubuntu-advantage                     active     10  ubuntu-advantage            latest/stable  143  no       Attached (esm-apps,esm-infra,landscape,livepatch)

Relevant log output

Confidential, please ask if required.

Additional context

No response