Don't wait for the greeter before running the display setup script

Currently, the display setup script is ran at two different places:
- With auto login, it is ran after X is ready
- Without auto login, it is ran after the greeter is ready

The script is now always ran after X is ready, this seem to work
around Qt bug #39552
Fix greeter socket error with Qt 5 due to the socket needing root access

The socket is created from the daemon which is ran as root, and it is
given UserAccessOption which means only the root user can access it.

Considering the greeter is ran under the sddm user, this prevents it
from connecting to the daemon in some cases.
Merge branch 'AnAkIn1-displaysetupscriptfix'