Distinguish hot launch and relaunch in trace

Sync the trace name as metrics.

Bug: 172528316
Flag: EXEMPT correct trace name
Test: Enable trace.
      Launch an app which doesn't handle uiMode change.
      Return to home. Toggle dark theme.
      Launch the app again.
      The trace contains "launchingActivity#1:completed-relaunch:pkg".
Change-Id: Ief7f05f6094bde272dd0b4b78454343f11305122