fix(sterni/mod/minecraft-fabric): correctly set service enable opt

This actually allows disabling a service for the first time, since the
configuration structure for the service is created irrespective of the
enable option.

Change-Id: I08e5e67565d6fe210fb0f65600b8750433ce4712
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10175
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI

users/sterni/modules/minecraft-fabric.nix

@@ -468,11 +468,11 @@ in
       (name: instanceCfg:
         {
           name = "minecraft-fabric-${name}";
-          inherit (instanceCfg) enable;
           value = {
             description = "Minecraft server ${name} with the fabric mod loader";
             wantedBy = [ "multi-user.target" ];
             after = [ "network.target" ];
+            inherit (instanceCfg) enable;
 
             serviceConfig = {
               Type = "simple";