Loadpoint: ignore charger our of sync if vehicle is disconnected

[andig]

In https://github.com/evcc-io/evcc/pull/12876/files#diff-c456526d4bd9022a488ce32de208b40d86016e2c40b0c81a2dffe557c186377dL709-R723, syncCharger was cleaned up. Particularly, the desired logic of ignoring warnings when vehicle was disconnected like

^(lp.enabled && ^lp.connected)

was changed to

!lp.enabled && !lp.connected

which is NOT equivalent. Instead, this would be equivalent:

!lp.enabled || lp.connected

This PR uses enabled as being the actual state of the charger:

!enabled || lp.connected