modemmanager: fix missing mmcli binary in service definition

hosts/common/programs/mmcli.nix

@@ -1,7 +1,11 @@
 { pkgs, ... }:
 {
   sane.programs.mmcli = {
-    packageUnwrapped = pkgs.modemmanager-split.mmcli;
+    packageUnwrapped = pkgs.modemmanager-split.mmcli.overrideAttrs (upstream: {
+      meta = upstream.meta // {
+        mainProgram = "mmcli";
+      };
+    });
     # TODO: sandbox
   };
 }

hosts/common/programs/modemmanager.nix

@@ -9,6 +9,10 @@ in
          sed 's/"root"/"networkmanager"/g' $out/share/dbus-1/system.d/org.freedesktop.ModemManager1.conf \
            > $out/share/dbus-1/system.d/networkmanager-org.freedesktop.ModemManager1.conf
        '';
+
+       meta = upstream.meta // {
+         mainProgram = "ModemManager";
+       };
     });
     # mmcli needs /run/current-system/sw/share/dbus-1 files to function
     enableFor.system = lib.mkIf (builtins.any (en: en) (builtins.attrValues cfg.enableFor.user)) true;
@@ -57,9 +61,9 @@ in
 
     # only if started with `--debug` does mmcli let us issue AT commands like
     # `mmcli --modem any --command=<AT_CMD>`
-    serviceConfig.ExecStart = "${cfg.package}/bin/ModemManager --debug";
+    serviceConfig.ExecStart = "${lib.getExe cfg.package} --debug";
     # --debug sets DEBUG level logging: so reset
-    serviceConfig.ExecStartPost = "${cfg.package}/bin/mmcli --set-logging=INFO";
+    serviceConfig.ExecStartPost = "${lib.getExe config.sane.programs.mmcli.package} --set-logging=INFO";
 
     serviceConfig.Restart = "on-abort";
     serviceConfig.StandardError = "null";