Refactor code to be used in LauncherLily features

Refactor add to workspace code to be used in Lily Launcher.
Also utilising code swap feature to swap out functionality of sorting
items on workspaces and finding next vacant space.

Bug: b/218186705
Test: Manually tested Launcher3 works.
Change-Id: I42a44eabeb307e1d23ef333e0a169437f9062bb6