Split OverviewState for IconRecents Go

Split common functionality in OverviewState so that it can be reused in
both implementations for IconRecents Go and non-Go.

Bug: 114136250
Test: Manual test NexusLauncher, Launcher3GoWithQuickstep
Test: Manual test IconRecentsGo (gets to recents screen w/o crashing)
Change-Id: Ibff5d3573b3b22dcdfda1b0662d4dd219d2e382f