fix app binder tracing on userdebug builds

All apps are profileable on debuggable builds, so enable binder
tracing during app startup on debuggable builds if binder tracing has
already been enabled.

Test: binder tracing shows up for new apps on userdebug
Bug: 156259316
Change-Id: I8cc6c2f711943c21b54f346a23ba7089dc9c9180