### 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)

SHC_PROCESS_DPI_UNAWARE = 0,
	SHC_PROCESS_SYSTEM_DPI_AWARE = 1,
	SHC_PROCESS_PER_MONITOR_DPI_AWARE = 2
} SHC_PROCESS_DPI_AWARENESS;
bool DisplayServerWindows::is_dark_mode_supported() const {
	return ux_theme_available;
}
bool DisplayServerWindows::is_dark_mode() const {
	return ux_theme_available && ShouldAppsUseDarkMode();
}
Color DisplayServerWindows::get_accent_color() const {
	if (!ux_theme_available) {
		return Color(0, 0, 0, 0);
	}
	int argb = GetImmersiveColorFromColorSetEx((UINT)GetImmersiveUserColorSetPreference(false, false), GetImmersiveColorTypeFromName(L"ImmersiveSystemAccent"), false, 0);
	return Color((argb & 0xFF) / 255.f, ((argb & 0xFF00) >> 8) / 255.f, ((argb & 0xFF0000) >> 16) / 255.f, ((argb & 0xFF000000) >> 24) / 255.f);
}
int DisplayServerWindows::tablet_get_driver_count() const {