xdg_activation_v1 not working with popovers

Steps to reproduce

1. Open GNOME Text Editor
2. Open Nautilus
3. Open a file in GNOME Text Editor via the context menu -> Open with Text Editor

Current behavior

GNOME Shell shows a "Text Editor is ready" notification

Expected outcome

Text Editor gets focus

Version information

• GTK 4.10.1
• GNOME Shell 44.0 with 44.0 applications
• NixOS unstable

Additional information

I did some debugging and this is caused by GTK chosing not to pass a surface to the xdg_activation_v1 interface here.

Basically since the click is done in a popover, wl_surface is NULL (probably because gdk_wayland_device_get_focus returns NULL).

This causes Mutter to reject the activation here as it requires both seat and surface to be present to consider the activation safe to perform.

Tagging @carlosg as you did most of the implementation on both sides.