Remove RemoteInput onWindowDetach

ag/20794576 caused regressions related to Notification's Keyboard usages in Heads Up b/295134107 and b/303437237.
RemoteInputView with ag/20794576 removes all remote input instances on keyboard close and notifications can't capture the keyboard focus again.

This CL basically reverts ag/20794576 and solves b/227115380 by removing specific remote input on Window Detach. As RemoteInputView is detached from window, we don't need its RemoteInput entry in RemoteInput Controller.

Flag: NONE
Fixes: 295134107
Fixes: 303437237
Fixes: 227115380
Test: 295134107-> Receive HUN Notification with Reply. Press Inline Reply to launch IME. Close IME via click down arrow left corner. Press inline Reply Again. Observe IME is launched.
Test: 303437237 -> Receive HUN Notification with Reply. Press Inline Reply to launch IME. Pull down the shade. Observe IME is not closed and focus is protected.
Test: 227115380 -> Receive HUN Notification without style that removes RemoteInput actions after inline reply. Click Inline Reply and Reply notification. Observe footer menu is visible.

Change-Id: Iafe1c0306499a662823912a4bda125954e05643a