Add INPUT_FEATURE_NO_INPUT_CHANNEL feature to app handle

The app handle doesn't need input features because its input is actually
handled by the InputMonitor in DesktopModeWindowDecorViewModel. Adding
this flags skips a IWindowSession::grantInputChannel, which helps with
jank when opening a fullscreen/split-screen task.

This change also unifies this new param with
mAllowCaptionInputFallthrough into a RelayoutParams#inputFeatures field.

Bug: 335975211
Test: atest WMShellUnitTests
Test: manual - app handle in fullscreen/split works as usual
Change-Id: I1b3b736e92a23f59d8174586da2902cff5ba5793