Don't output escape codes for the cursor when the tui isn't active

[ealmloff]

Fixes #4535

[jkelleyrtp]

Technically the show_cursor code is meant for the dx new and dx init commands in the event cargo generate fails. The TUI being active is not set there, so we wouldn't be catching that case.

We can extract the tui_active bool back to a static and then set it in the relevant places. Should be nicer to not pass it around as an arg.

I think there might be a way to check if "alternate mode" is enabled without our own book. IIRC there's a method on stdout that lets you check

[ealmloff]

Ah, tui_active will also silence logs which I don't think we want for the dx new and dx init commands. I switched to checking if stdout is a terminal