Migrate Message demos from radio to select #433
Description
From @thatblindgeye:
In addition to the file comments below, a non-blocker for this PR would be switching from radio buttons for these examples and using a Select instead -- would reduce the space taken up, but would also allow more unique labeling for the Selects (right now there's basically 2+ radio buttons with the same labels on the page: 2 for "Table" etc). Again non-blocking here if we wanted to open a followup for a docs update.