Skip some methods in BatchedRemoveStatusService when account is nil (#10095)

Skip some methods in BatchedRemoveStatusService when account is nil (#10095)

* Skip some methods in BatchedRemoveStatusService when account is nil

Sometimes `bin/tootctl accounts cull` fails with below error:

undefined method `followers_for_local_distribution' for nil:NilClass (NoMethodError)

This commit makes BatchedRemoveStatusService to skip below methods when
`account` is nil:

- unpush_from_home_timelines()
- unpush_from_list_timelines()
- batch_stream_entries()

* Fix rubocop error: Use `next` to skip iteration.