remove @Dependent parameter section for container events

Imo we can also get rid of the following paragraph in 6.4.2

" all @Dependent scoped contextual instances injected into method parameters of an observer method of any container lifecycle event, as defined in Section 11.5, “Container lifecycle events”, is destroyed after all observers of the Before- Shutdown event complete,"

The reason is that we clarified that only a BeanManager (and other Extensions?) can get injected into into an Extension.