template/host: Fix APT check name to match current apply rules

netbox_icinga_generator/templates/generic-host.j2

@@ -39,7 +39,7 @@ object Host "{{ vars.name }}" {
 	// === SYSTEM HEALTH CHECKS ===
 	{%- if vars.apt %}
 	// apt
-	vars.apt_{{ vars.apt }} = {}{% endif %}
+	vars.check_apt_{{ vars.apt }} = {}{% endif %}
 
 	// procs
 	{%- for check in vars.procs %}