trunctate large code inputs in the console (but make it possible to expand them expand)

This is just some dogfooding feedback.

I find that the code snippets that appear in the console can take up a lot of space, that for the most part is unnecessary.

What if it only showed the last line by default, with an option to expand to show the whole thing? (We already have the "jump to cell in editor button" which is super useful).

No files or tests are named. Start by locating the console component that renders code snippets and the existing jump-to-cell-in-editor button, then trace how the displayed code is assembled. Done means long snippets show only their last line by default and provide an option to expand to the full snippet.

Written by the indexing model from the issue text.