Make reason mandatory when interactive

[doomholderz]

Making reason entry mandatory on interactive console creations

[benwh]

While I'm no longer a maintainer on this repo, I can provide some historical context:

The runner package in this repo was designed to be relatively un-opinionated, mostly as an inspiration and something that you could use when developing against theatre. At GoCardless (and incident.io) we imported this package into our own CLI, and only in those CLI's would we encode organisation-specific logic like requiring a reason.

I don't think it's practical for anyone to be using the runner CLI here for their own organisation, given that it's not packaged and distributed nicely, hence I'd be against putting org-specific requirements into it.