Refs #33956 - Ensure mod_expires is loaded

In case only minimal Apache modules are loaded then mod_expires may not
be present. The result is that assets are sent without headers that
allow browsers to cache it.

manifests/config/apache.pp

@@ -154,8 +154,9 @@
   if $suburi {
     $custom_fragment = undef
   } else {
-    # mod_env is required by configuration in _assets.conf.erb
+    # mod_env and mod_expires are required by configuration in _assets.conf.erb
     include apache::mod::env
+    include apache::mod::expires
     $custom_fragment = file('foreman/_assets.conf.erb')
   }