Enforce platform level animation in CrossProfileApps.startMainActivity

With this change, whenever apps start an activity in another profile
using CrossProfileApps.startMainActivity, an animation will be enforced.
For now, we are showing the "open task" animation.
We may put something fancier if we have time in P.

Test: cts-tradefed run cts-dev --module DevicePolicyManager --test - com.android.cts.devicepolicy.CrossProfileAppsHostsideTest
Test: atest services/tests/servicestests/src/com/android/server/pm/crossprofile/CrossProfileAppsServiceImplTest.java
Bug: 70799822

Change-Id: I03525080151c6112633108419d69d64e76a511f3