Rendering: makes sure IsAvailable can be used during init of other services (#23817)
Rendering: makes sure IsAvailable can be used during init of other services (#23817)

* Rendering: makes sure service knows if it is configured after Init()

* Rendering: refactor
grafana/grafana,grafana/grafana,grafana/grafana,grafana/grafana,grafana/grafana,grafana/grafana,grafana/grafana