For managed profiles, use the parent user's default launcher

The default launcher for managed users is always the same as their
parent user.

Bug: 173643120
Test: atest com.android.server.pm.ShortcutManagerTest1
            com.android.server.pm.ShortcutManagerTest2
            com.android.server.pm.ShortcutManagerTest3
            com.android.server.pm.ShortcutManagerTest4
            com.android.server.pm.ShortcutManagerTest5
            com.android.server.pm.ShortcutManagerTest6
            com.android.server.pm.ShortcutManagerTest7
            com.android.server.pm.ShortcutManagerTest8
            com.android.server.pm.ShortcutManagerTest9
            com.android.server.pm.ShortcutManagerTest10
            com.android.server.pm.ShortcutManagerTest11
      atest CtsShortcutHostTestCases CtsShortcutManagerTestCases
Change-Id: I30ff608a6ada26006dc1e3d20ee6019751da0518