Fix Launcher3 issues due to hardcoded default user

Bug: 288407058
Bug: 288406660
Bug: 288406673
Test: atest NexusLauncherOutOfProcTests:com.android.launcher3.ui.TaplTestsLauncher3#testUninstallFromWorkspace
Test: atest NexusLauncherOutOfProcTests:com.android.launcher3.ui.TaplTestsLauncher3#testUninstallFromAllApps
Test: atest NexusLauncherOutOfProcTests:com.android.launcher3.ui.TaplTestsLauncher3#getIconsPosition_afterIconRemoved_notContained
Change-Id: Ibe0c4d8f21721e08b2496bfb5c470903e785c2c5