The redesign only offered a largest-first size sort. Keep the existing `size`
preference value as largest for compatibility with saved settings and add a new
ascending size key for users who want to find small downloads first.
The sort menu now exposes both size directions and the sorter handles the new
smallest-first option directly.
Test Plan:
- git diff --check
Refs: user redesign nitpick about Size (smallest) sort
ddidderr
25f92c9b0b
