The assistant adds files unlocked, even when git-annex is otherwise
configured to add them locked.

There are good reasons for that different behavior to be the default,
but it would be worth having a config to override that.

Eg, when annex.assistant.honor.addunlocked is set, honor the
annex.addunlocked configuration, which defaults to adding files locked.
Or perhaps a better name would be annex.assistant.allowaddlocked.

See here for some motivating use cases
<https://git-annex.branchable.com/forum/Is_there_a_way_to_have_assistant_add_files_locked__63__/>
