Add INVOCATION_TYPE_LAUNCHER_SYSTEM_SHORTCUT for VIS calls from SysUI launcher.

This change is so VIS apps running on AOSP and XR do not need special platform logic when handling new sessions.

Bug: 380946168
Change-Id: If2e55cb5dce5991f4322337aa82c69491e113c3b
Test: Confirmed it works with AGSA and XR Launcher with a local flash.
Flag: NONE adding an invocation type.