Add an opt-in to call onError anyway

[ZacSweers]

This way, if someone supplies their own LambdaConsumerIntrospection, they could control this behavior if they want (such as if theirs just logs an error)

[ZacSweers]

Note that this would require some reworking of internals to opt-in and allow it. Right now reportError always calls RxJavaPlugins.onError() anyway