Space and Enter should be synonymous

[kmcnaught]

In October's user testing, we found a lot of children used Space as a "confirm/enter" action by default. This works on native elements like the "Run code" button or scenario dropdown, but does not work in any of the block coding UI.

I believe we are in agreement that Space and Enter should remain synonymous throughout the application. I don't think this has been captured in any other issues.