Make the timeout for user removal 40 seconds in UserManagerTest.

BlockingBroadcastReceiver has 4 minutes of timeout by default. This
CL topic makes it customizable and sets it to 40 seconds for user
removal.

Bug: 267760314
Test: atest com.android.server.pm.UserManagerTest
Change-Id: Ib3017fd38357abe005a5a2aa5e9cd987cf5673ef