Add CastController to DumpManager

It seems to have gone missing from when we transitioned it away from
Dependency. This CL adds it to DumpManager so we can see its state in
bug reports

Test: adb shell dumpsys activity service SystemUI | grep CastController
Bug: 158713111
Change-Id: I33266fbc983d54e20efd9ba64dfef38a0f4ab218