Don't send users to the bulk action page after a single-item release

[andrewjbtw]

When users run a single-item release from an Argo show page, the system takes them to the bulk action page. This is somewhat disorienting given that no other action on a show page takes people away from the show page. We should instead show a banner like we do for other show page actions like "reindex" and "republish".

In terms of indicating when release is successful, the bulk action page and the bulk action log doesn't provide much information. All the release action does (if I understand correctly) is start the releaseWF, and it's the releaseWF that gives users the real information about success or failure. If starting the releaseWF itself fails, we should show a message but that too should be in a banner on the show page.

Additional context

I think this must have been implemented this way because single-item release was implemented as a bulk action, and there's some logical sense to taking people to the bulk action page when a bulk action runs. The decision predates me.

I'm not opposed to keeping single-item release a bulk action if it makes sense to do that, but it doesn't seem like we need to if single-item publish, single-item reindex, and single-item "add workflow" don't use bulk actions.