Fix editor controls working in game mode

-Implements ResetInputChannels for ViewportController API and SetEnabled for ViewportControllerList
-Disables all viewport controllers while in game mode

Code/Sandbox/Editor/LegacyViewportCameraController.h

@@ -35,6 +35,7 @@ namespace SandboxEditor
         explicit LegacyViewportCameraControllerInstance(AzFramework::ViewportId viewport);
 
         bool HandleInputChannelEvent(const AzFramework::ViewportControllerInputEvent& event) override;
+        void ResetInputChannels() override;
         void UpdateViewport(const AzFramework::ViewportControllerUpdateEvent& event) override;
 
     private:
@@ -53,6 +54,7 @@ namespace SandboxEditor
         bool HandleMouseMove(const AzFramework::ScreenPoint& currentMousePos, const AzFramework::ScreenPoint& previousMousePos);
         bool HandleMouseWheel(float zDelta);
         bool IsKeyDown(Qt::Key key) const;
+        void UpdateCursorCapture(bool shouldCaptureCursor);
 
         bool m_inRotateMode = false;
         bool m_inMoveMode = false;