authentik: fix quadlet v1 generator dialect on this host

Probed the live generator on dankclaw: podman 5.x v1 hard-fails unit
generation on dash-prefixed options (--shm-size killed authentik-server's
unit) and rejects Command= entirely; Exec= is the accepted role selector.
Drop --shm-size (uwsgi uses unix sockets under /run, not /dev/shm; default
64m shm is fine) and drop systemctl --user enable — generated units are
transient and cannot be enabled; WantedBy=default.target in each unit file
is what makes them boot-persistent on this generator.

dankclaw/authentik/quadlet/authentik-server.container

@@ -30,7 +30,6 @@ Environment=AUTHENTIK_POSTGRESQL__PASSWORD=${AUTHENTIK_PG_PASS}
 Environment=AUTHENTIK_SECRET_KEY=${AUTHENTIK_SECRET_KEY}
 PublishPort=127.0.0.1:9000:9000
 HealthCmd=python -c "import urllib.request;urllib.request.urlopen('http://localhost:9000/-/health/')"
---shm-size=512m
 HealthInterval=30s
 HealthTimeout=10s
 HealthRetries=5