Both services carried an `sso.enable` defaulting to false, so a swarm's
own forge and homeserver shipped with their identity provider switched
off unless an operator remembered two lines. Grafana never had the
toggle and is the shape the other two now match.
Behaves as if the setting were true: `ssoLocal` loses one conjunct, the
three assertions become unconditional, and the login source and
identity_provider render always.
The option is removed rather than defaulted, so a config that turned SSO
OFF fails where that line is instead of silently gaining a login
provider on the next rebuild.
792d7f503f