Make SysUI dialogs more consistent

This CL makes SysUI dialogs more consistent by ensuring they are using
the same button styles and paddings. I decided to be strongly
opinionated: the primary buttons are all filled and on the right, the
secondary button are hairline and on the left.

See b/203666386#comment13 for a video.

Bug: 203666386
Test: Manual
Change-Id: I587d9537309357555229db411edfb154151a92e7
Merged-In: I587d9537309357555229db411edfb154151a92e7