shell_integration: Fix disappearing context menus on Windows #2898

shell_integration: Fix disappearing context menus on Windows #2898

Since each new connection to the socket API would trigger a broadcast
of REGISTER_PATH to all existing connections, opening the context menu
would trigger a SHChangeNotify call of the root directory through
the overlay icon extension, which is currently also connected to the
socket API, waiting for changes.

Fix the issue by sending the initial REGISTER_PATH automatic response
only to the connecting socket.