Revert "nixos/postfix-tlspol: make tlsrpt depend on tlsrpt service"

This reverts commit 9ccec77537.

Per the author of postfix-tlspol in
https://github.com/NixOS/nixpkgs/pull/456728#issuecomment-3536706358

> QUERYwithTLSRPT should be used when the installed Postfix version is
> 3.10 or newer, regardless of the state of the TLSRPT option in the
> Postfix configuration. Especially Postfix 3.10.5 and later use the
> additional data provided by postfix-tlspol to find the correct MX
> domains to connect to MTA-STS-protected mail destinations.
>
> If you use QUERY with Postfix 3.10.5+, Postfix will use the legacy
> way of DNS MX lookup for the domain, which theoretically can differ
> from the hosts provided by the MTA-STS policy (but usually should be
> the same).
>
> The user can still disable TLSRPT in the Postfix configuration without
> side-effects.

nixos/modules/services/mail/postfix-tlspol.nix

@@ -142,7 +142,7 @@ in
               else
                 "inet:${cfg.settings.server.address}";
           in
-          [ "socketmap:${address}:${if config.services.tlsrpt.enable then "QUERYwithTLSRPT" else "QUERY"}" ];
+          [ "socketmap:${address}:QUERYwithTLSRPT" ];
       };
 
       systemd.services.postfix = {