Revisit the need to set `FACTORY_BEAN_OBJECT_TYPE` on repository bean definitions

[odrotbohm]

IIRC, we only introduced setting the attribute to work around in a —likely fixed in the meantime — limitation in Spring Framework. As we now even need to load the repository interface to set the attribute (see #2891) we should revisit that practice to potentially be able to avoid that as we now have to load the repository interface twice. First time in RepositoryConfigurationExtensionSupport.getRepositoryConfigurations(…), unless we significantly refactor the way we create the bean definitions.