Changed Grid layout on home. More space at the bottom.

Bug: http://b/issue?id=3053235

This is a proper way to do what was done in https://android-git.corp.google.com/g/#change,71522

The longAxisEndPadding used to be equal to button_bar_height.
Increased it to match proposed mock from designers and increase space
between last row and hot seats buttons.

Change-Id: I31dfba0a3e90a30f18d42b16681592d9527517d4
1 file changed