Summary:
Fixes layout issue that was caused by ANT line-heights leaking into the old design.
Introduced a `.flipperlegacy_design ` class at the `root` element of Flipper, so that it is easier in the future to bail out / add overrides for certain features in the old design.
Reviewed By: priteshrnandgaonkar
Differential Revision: D24135482
fbshipit-source-id: 40091ebbde71662f2ebea66577f7b727009ca9c6
02570136ce