### 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)

Size2i DisplayServerWindows::window_get_size(WindowID p_window) const {
	_THREAD_SAFE_METHOD_
	ERR_FAIL_COND_V(!windows.has(p_window), Size2i());
	const WindowData &wd = windows[p_window];
	
	if (wd.minimized) {
		return Size2(wd.width, wd.height);
	}
	RECT r;
	if (GetClientRect(wd.hWnd, &r)) { 
		return Size2(r.right - r.left, r.bottom - r.top);
	}
	return Size2();
}
Size2i DisplayServerWindows::window_get_size_with_decorations(WindowID p_window) const {
	_THREAD_SAFE_METHOD_
	ERR_FAIL_COND_V(!windows.has(p_window), Size2i());
	const WindowData &wd = windows[p_window];
	RECT r;
	if (GetWindowRect(wd.hWnd, &r)) { 
		return Size2(r.right - r.left, r.bottom - r.top);
	}
	return Size2();
}
void DisplayServerWindows::_get_window_style(bool p_main_window, bool p_fullscreen, bool p_multiwindow_fs, bool p_borderless, bool p_resizable, bool p_maximized, bool p_no_activate_focus, DWORD &r_style, DWORD &r_style_ex) {
	
	
	
	r_style = 0;
	r_style_ex = WS_EX_WINDOWEDGE;