ArC: revise the construction of client proxies

[mkouba]

Description

Currently, not all bean types which are Java interfaces are implemented by the client proxy. Instead, the client proxy extends the implementation class of the bean.

This is not a problem in most cases, esp. for class-based/producer beans where the set of bean types reflects the class hierarchy. However, it's not 100% when the set of bean types is restricted via @Typed.

[quarkus-bot]

/cc @Ladicek (arc), @manovotn (arc)