Implement all virtual functions from InputEventNotificationBus (#340)

Signed-off-by: Michał Pełka <[email protected]>

Gems/ROS2/Code/Source/VehicleDynamics/ManualControlEventHandler.h

@@ -44,10 +44,20 @@ namespace ROS2::VehicleDynamics
         AZStd::string m_eventName;
         OnHeldHandlerFunction m_handler;
 
+        void OnPressed(float value) override
+        {
+            m_handler(value);
+        }
+
         void OnHeld(float value) override
         {
             m_handler(value);
         }
+
+        void OnReleased([[maybe_unused]] float value) override
+        {
+            m_handler(0);
+        }
     };
 
     //! Registers to "steering" and "acceleration" input events, and translates them into vehicle inputs