8d8eba000f
The REPLACE flag we currently pass is useless, as replacing the service is disallowed when not started with the ALLOW_REPLACEMENT flag. Fix this by adopting a more standard pattern where replacement is always allowed, but only actually requested when `--replace` is passed on the command line. Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2152>