Alphabetize all element-deps

Change-Id: Idc31d60daeea61d6df0b70dac4a5671fa5a804ee
Enforce alphabetical ordering of element-deps

We've started to require this in reviews, so we should really have
automation in place to catch it right away.

Change-Id: I43fd90647acba400cea11c665fb587856514b0ee