Adds LauncherApps#ShortcutChangeCallback

This CL only defines the APIs and the aidl layer. LauncherAppsService
changes will be added in a separate CL.

Bug: 148085769
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
Change-Id: I9590cd7e2ad2b0336280f23a2766e242158ceb4a