Ensure userId is set in TCEvent.

Part of security fix in I2fdffd8eb4221782cb1f34d2ddbe41dd3d36595c

TCContexts that existed outside a TC session did not have userId
set by the SystemTC. This CL ensures SystemTC always sets the
userId for all TCEvents (and deprecated SelectionEvents).

Bug: 136483597
Test: atest android.view.textclassifier
      Manual test ensuring that ConvActions was logging TCEvent with
      userId.

Change-Id: Ie2a362f8f4758d5dc0390aeb2dbf23f9d78a378e