Refine style picker layout (1/2)

 - Change options border to 8dp, https://docs.google.com/presentation/d/15JadcGi5k1_0znUN_XdFpU7UxeXwxjK3Y7LxvhW5ETM/edit?ts=5eb5f9a8#slide=id.g777aaff414_1_0
 - Fix the options will be truncated when display size large,
 before: https://screenshot.googleplex.com/j1GckxT9fxU.png
 after: https://screenshot.googleplex.com/LMEzQwjz2Vc.png

Change-Id: Id238bb1c0c31471c43f50c4ff0e2a37f6b24dd61