Remove unnecessary warning

[stuartwdouglas]

This warning can be triggered by legitimate code, but won't identify
real problems as a private type would be in the same index as the
current class.

[mkouba]

This warning can be triggered by legitimate code,

What legitimate code do you have in mind?

[stuartwdouglas]

Won't it get triggered if you have a class as a parameter that is outside an application archive?

[mkouba]

Won't it get triggered if you have a class as a parameter that is outside an application archive?

Only if it's not possible to index the class using the Thread.currentThread().getContextClassLoader(); see https://github.com/quarkusio/quarkus/blob/main/independent-projects/arc/processor/src/main/java/io/quarkus/arc/processor/BeanArchives.java#L102-L109.