fix(em): update default map (#3977)

Changed defaultmap value from "emp_district" to "con_district402" as this map was renamed years ago and would otherwise cause the server to fail on startup.

lgsm/config-default/config-lgsm/emserver/_default.cfg

@@ -13,7 +13,7 @@ ip="0.0.0.0"
 port="27015"
 clientport="27005"
 sourcetvport="27020"
-defaultmap="emp_district"
+defaultmap="con_district402"
 maxplayers="62"
 
 ## Game Server Login Token (GSLT): Optional