Search for a covariant type when checking if a component's abstract property has been implemented

[eygraber]

The following code causes an error:

Cannot find an @Inject constructor or provider for: AppComponent

interface AppComponent

abstract class SessionComponent {
    abstract val appComponent: AppComponent
}

@Component
abstract class InheritedAppComponent : AppComponent

@Component
abstract class InheritedSessionComponent(
    @Component override val appComponent: InheritedAppComponent,
) : SessionComponent()

It looks like #326 was too aggressive in fixing #309