Removed InputManager.focusState property since only the setter was used

- Replaced the one line where the setter was used with directly updating the runtime's focus state. This was done to remove questions about the fallback case for the getter if there was no runtime set.

Author: chris-massie

Packages/com.unity.inputsystem/InputSystem/Runtime/InputManager.cs

@@ -264,22 +264,6 @@ public InputSettings.ScrollDeltaBehavior scrollDeltaBehavior
             }
         }
 
-        public FocusFlags focusState
-        {
-            get
-            {
-                if (m_Runtime != null)
-                    return m_Runtime.focusState;
-
-                return Application.isFocused ? FocusFlags.ApplicationFocus : FocusFlags.None;
-            }
-            set
-            {
-                if (m_Runtime != null)
-                    m_Runtime.focusState = value;
-            }
-        }
-
         public float pollingFrequency
         {
             get
@@ -3925,8 +3909,7 @@ private void ProcessDeviceConfigurationEvent(InputDevice device)
         private unsafe void ProcessFocusEvent(InputEvent* currentEventReadPtr)
         {
             var focusEventPtr = (InputFocusEvent*)currentEventReadPtr;
-            FocusFlags state = focusEventPtr->focusFlags;
-            focusState = state;
+            m_Runtime.focusState = focusEventPtr->focusFlags;
 
 #if UNITY_EDITOR
             SyncAllDevicesWhenEditorIsActivated();