0032638: Draw Harness, ViewerTest - HTML input range misbehavior in WebAssembly

0032638: Draw Harness, ViewerTest - HTML input range misbehavior in WebAssembly

ViewerTest_EventManager - added tracking of EMSCRIPTEN_EVENT_FOCUSOUT event.
onWasmMouseCallback() has been adjusted to return FALSE for EMSCRIPTEN_EVENT_TARGET_WINDOW
target to avoid misbehavior of other HTML controls.

WNT_Window::ProcessMessage() now handles WM_SETFOCUS/WM_KILLFOCUS instead of WM_ACTIVATE to track focus changes.

AIS_ViewController::ProcessFocus() now redirects to AIS_ViewController::ResetViewInput() on focus loss.
This fixes issues when key action (like WASD navigation) keep working even after releasing key if window has been switched.