Center AllApps on the screen

AllApps used workspace paddings which are unbalanced in verticalBar. This changes it to always be centered. In dynamic grid AllApps now uses the whole width for the layout. In responsive grid it keeps the cell width and center the layout.

Note that this is centered on the screen but nothing could be done regarding the camera inset at this time, as it would need a refactor of how AllApps QSB is layout as well.

Bug: 269632571
Test: NexusLauncherTest
Flag: ACONFIG com.android.launcher3.enable_responsive_workspace TEAMFOOD
Change-Id: I326d041bcef211d398d1a5c3210958b689414d49