### 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)

_THREAD_SAFE_METHOD_
	ERR_FAIL_COND_V(!windows.has(p_window), Size2i());
	const WindowData &wd = windows[p_window];
	return wd.max_size;
}
void DisplayServerWindows::window_set_min_size(const Size2i p_size, WindowID p_window) {
	_THREAD_SAFE_METHOD_
	ERR_FAIL_COND(!windows.has(p_window));
	WindowData &wd = windows[p_window];
	if ((p_size != Size2()) && (wd.max_size != Size2()) && ((p_size.x > wd.max_size.x) || (p_size.y > wd.max_size.y))) {
		ERR_PRINT("Minimum window size can't be larger than maximum window size!");
		return;
	}
	wd.min_size = p_size;
}
Size2i DisplayServerWindows::window_get_min_size(WindowID p_window) const {
	_THREAD_SAFE_METHOD_
	ERR_FAIL_COND_V(!windows.has(p_window), Size2i());
	const WindowData &wd = windows[p_window];
	return wd.min_size;
}
void DisplayServerWindows::window_set_size(const Size2i p_size, WindowID p_window) {