No feedback on no operation selected

[jrozner]

If you don't have an operation selected (eg. new install that hasn't communicated with a server yet) and attempt to capture evidence (any kind) ashirt will silently fail and not provide any feedback to the user as to why. We should add a toast notification (or something equivalent) with an error message.

[JoelAtDeluxe]

~~I'm pretty sure we used to have one. I'll see if I can figure out what happened / try to add it back in.~~

We still do have this (here) , and it is currently working on linux (in the main branch). It might be a Mac specific issue. I'll try to get that checked out soon, but I don't have a mac workspace set up for this currently.