UX: Add ESC key support to close new workspace modal

[james2doyle]

I keep opening the new workspace dialog by accident as I get used to the new keyboard shortcuts (coming from Cmux) and I noticed that you can’t close the dialog unless you click close explicitly. So can support for pressing ESC to close the "Open Folder as Workspace" modal dialog be added?

If yes, I can create a PR for that.

[bvolpato]

yes, this makes sense. The workspace prompt is a custom GTK window today, so it does not get standard dialog Escape handling. A focused PR that closes this window on Escape would be great. Please keep the nested folder picker behavior unchanged and run the normal quality and GTK smoke checks. thanks for offering to take it.