Fix Anaconda startup from app launcher on Live

We recommend use of application launcher in installation instructions
but Anaconda won't start until xhost application is started.

It's already solved by starting xhost app in ~/.bashrc, however, that
won't work for a launcher because it's not sourcing ~/.bashrc. To solve
this, start xhost by Sway configuration file on Live.

sway/config.live.d/99-xhost-allow-liveinst.conf

+# Allow local root to connect to Xwayland.
+# Anaconda runs elevated and will fail to start without that.
+
+#
+# Requires:     xhost
+
+exec xhost si:localuser:root