### Godot version

v4.0.beta17.mono.official [c40020513]

### System information

Windows 11 22H2

### Issue description

If a focused subwindow is destroyed, DisplayServerWindows may still attempt to send mouse motion events to that window, because `last_focused_window` isn't updated until another window is focused.

```
ERROR: Condition "!windows.has(p_window)" is true. Returning: Point2i()
   at: window_get_position (platform/windows/display_server_windows.cpp:999)
```

### Steps to reproduce

Run the MRP, click some non-Godot application window to focus it, then click the "CLOSE" button in the secondary window. This destroys the window without re-focusing the main window, so hovering the mouse over the main window will produce the error message above.

### Minimal reproduction project

[native_windows_hover.zip](https://github.com/godotengine/godot/files/10573386/native_windows_hover.zip)

}
			}
		} break;
		case WM_CLOSE: 
		{
			if (windows[window_id].focus_timer_id != 0U) {
				KillTimer(windows[window_id].hWnd, windows[window_id].focus_timer_id);
			}
			_send_window_event(windows[window_id], WINDOW_EVENT_CLOSE_REQUEST);
			return 0; 
		}
		case WM_MOUSELEAVE: {
			if (window_mouseover_id == window_id) {
				old_invalid = true;
				window_mouseover_id = INVALID_WINDOW_ID;
				_send_window_event(windows[window_id], WINDOW_EVENT_MOUSE_EXIT);
			} else if (window_mouseover_id != INVALID_WINDOW_ID && windows.has(window_mouseover_id)) {
				
				
				track_mouse_leave_event(windows[window_mouseover_id].hWnd);
			}
		} break;
		case WM_INPUT: {
			if (mouse_mode != MOUSE_MODE_CAPTURED || !use_raw_input) {
				break;
			}
			UINT dwSize;
			GetRawInputData((HRAWINPUT)lParam, RID_INPUT, nullptr, &dwSize, sizeof(RAWINPUTHEADER));
			LPBYTE lpb = new BYTE[dwSize];
			if (lpb == nullptr) {