fix: set SystemD Unit modes to '0644' to make complaining log messages go away

tasks/install_subapp.yml

@@ -60,7 +60,7 @@
     dest: "/etc/systemd/user/{{ item }}"
     owner: "{{ vault_subapp_vars.files.subapp.owner }}"
     group: "{{ vault_subapp_vars.files.subapp.group }}"
-    mode: "{{ vault_subapp_vars.files.subapp.mode | default('0400') }}"
+    mode: "0644"
   loop:
     - "disapp.service"
     - "subapp.service"