Refactoring carousel to not resize non-carousel embeddables

[#49877927]
See https://www.pivotaltracker.com/story/show/49883371 for the comment where this cropped up: the resizing was happening regardless of whether the carousel was actually needed, and in some cases it was setting the embeddable max-height to 0, which caused layout issues.
Separating questions from buttons [#49877927]

https://www.pivotaltracker.com/story/show/49877927