lieer-service: add path to notmuch config (#1704)

This change makes the services created via the lieer module aware of the notmuch config created by the home-mangager notmuch module (which is stored in a non-standard location).

Without this change all the lieer services created by the lieer module failed for me, as they were unable to find the notmuch config.

modules/services/lieer.nix

@@ -26,6 +26,8 @@ let
         Type = "oneshot";
         ExecStart = "${pkgs.gmailieer}/bin/gmi sync";
         WorkingDirectory = account.maildir.absPath;
+        Environment =
+          "NOTMUCH_CONFIG=${config.xdg.configHome}/notmuch/notmuchrc";
       };
     };
   };

tests/modules/services/lieer/lieer-service-expected.service

@@ -1,4 +1,5 @@
 [Service]
+Environment=NOTMUCH_CONFIG=/home/hm-user/.config/notmuch/notmuchrc
 ExecStart=@lieer@/bin/gmi sync
 Type=oneshot
 WorkingDirectory=/home/hm-user/Mail/hm@example.com