Switched TaskRecord.mService to ActivityTaskManagerService (6/n)

Objects that contain or represent activities like TaskRecord can
no longer rely on ActivityManagerService as it is going to be in a
different package.

Test: Existing tests pass
Test: go/wm-smoke-auto
Bug: 80414790

Change-Id: Ia17591f7d709839c18762d1eb2474b2e2f649dfc