Distinguish process-switch for launch trace

So the perfetto processor won't recognize in-app transition
as an app startup.

Bug: 231612200
Test: Launch Settings from launcher and enter sub settings.
      There will be 2 "launching: com.android.settings" but
      only one trace at "Android App Startups".
Change-Id: I14a4fc1981e69dd27e2a5027f519db2dab4fff9f