Dispose InputChannel when dispose InputEventReceiver

There would be an error if an InputChannel didn't be disposed before
finalized. The client InputChannel created by ViewRootImpl or SystemUI
that would also create an InputEventReceiver to receive input events, and hold
the client InputChannel, so if the InputEventReceiver is going to be disposed,
the InputChannel should be disposed as well.

Test: manual
Bug: 128679213
Change-Id: I24c16f032403e8a982a84a5e0adbfabcdc016f0f