allow proxying of classes with non-private final methods

Currently we explicitly disallow proxying of classes with non-private final methods.

EJB does allow this. And there are a few final methods in the JDK and other libs. E.g. HashMap#initHashSeedAsNeeded. Currently we cannot have a producer method for it.

We might rethink our decision and allow it. Probably with an own annotation like @AllowProxying which disables this check for certain cases (subclass managed-beans or producers).