Fix MSMTP Mailu routine loading condition

- Correct grouping of reachability check
- Replace incorrect boolean cast for mailu_token with length check
- Load Mailu routines only when host is unreachable or token is missing

Details: https://chatgpt.com/share/692f1e58-0d6c-800f-9699-e9a26f1e8db9

roles/sys-svc-msmtp/tasks/01_core.yml

@@ -19,10 +19,14 @@
   when:
     - "'web-app-mailu' in group_names"
     - >
-        (mail_host_reachability is defined and
-         (mail_host_reachability.status | default(0) | int) != 200)
+        (
+          mail_host_reachability is defined and
+          (mail_host_reachability.status | default(0) | int) != 200
+        )
         or
-        not (users['no-reply'].mailu_token | default(false) | bool)
+        (
+          users['no-reply'].mailu_token | default('', true) | length == 0
+        )
 
 - name: install msmtp msmtp-mta
   community.general.pacman: