Use vars value rather than hardcoded value

Co-authored-by: Nick <50747025+mcdonnnj@users.noreply.github.com>

Author: jsf9k

tasks/main.yml

@@ -42,7 +42,7 @@
     # provided by systemd-resolved.
     no_extra_spaces: true
     option: DNSStubListener
-    path: /etc/systemd/resolved.conf
+    path: "{{ config_file }}"
     section: Resolve
     value: "{{ systemd_resolved_dns_stub_listener }}"