fixes BUG-52188: ExternalSystem instances are leaked
Injecting @Depedent scoped ExternalSystem instances in @ApplicationScoped ExternalSystemProvider caused the former instances to be retained as part of the latte's context. Each HttpExternalSystem references to a JDK's HttpClient intance which causes its threads and file descriptors to be kept open forever even after the ExternalSystem is disposed from the cache.
Instantiating them through the BeanManager (which is indirectly done by the WeldUtils) prevents this leak