### 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)

DWORD dwExStyle;
	DWORD dwStyle;
	_get_window_style(window_id_counter == MAIN_WINDOW_ID, (p_mode == WINDOW_MODE_FULLSCREEN || p_mode == WINDOW_MODE_EXCLUSIVE_FULLSCREEN), p_mode != WINDOW_MODE_EXCLUSIVE_FULLSCREEN, p_flags & WINDOW_FLAG_BORDERLESS_BIT, !(p_flags & WINDOW_FLAG_RESIZE_DISABLED_BIT), p_mode == WINDOW_MODE_MAXIMIZED, (p_flags & WINDOW_FLAG_NO_FOCUS_BIT) | (p_flags & WINDOW_FLAG_POPUP), dwStyle, dwExStyle);
	RECT WindowRect;
	WindowRect.left = p_rect.position.x;
	WindowRect.right = p_rect.position.x + p_rect.size.x;
	WindowRect.top = p_rect.position.y;
	WindowRect.bottom = p_rect.position.y + p_rect.size.y;
	int rq_screen = get_screen_from_rect(p_rect);
	if (rq_screen < 0) {
		rq_screen = get_primary_screen(); 
	}
	if (p_mode == WINDOW_MODE_FULLSCREEN || p_mode == WINDOW_MODE_EXCLUSIVE_FULLSCREEN) {
		Rect2i screen_rect = Rect2i(screen_get_position(rq_screen), screen_get_size(rq_screen));
		WindowRect.left = screen_rect.position.x;
		WindowRect.right = screen_rect.position.x + screen_rect.size.x;
		WindowRect.top = screen_rect.position.y;
		WindowRect.bottom = screen_rect.position.y + screen_rect.size.y;
	} else {
		Rect2i srect = screen_get_usable_rect(rq_screen);
		Point2i wpos = p_rect.position;
		if (srect != Rect2i()) {
			wpos.x = CLAMP(wpos.x, srect.position.x, srect.position.x + srect.size.width - p_rect.size.width / 3);
			wpos.y = CLAMP(wpos.y, srect.position.y, srect.position.y + srect.size.height - p_rect.size.height / 3);