Fix layering for app dependency within platform

[andy31415]

#36939 introduced a nogncheck to access code from app within platform, breaking layering. This breaks compilation by not requiring some things like appconfig or other generated headers that are used by interactionmodelengine (which is a huge class/dependency) during platform configuration.

Instead, platform should find a different signaling way: in this case we likely want to have some notification mechanism (e.g. from main or from the init server) that providers are set up.