Fix handling of config vars with eval expression (#29536)

The config variables defined with eval, like INVENTORY_IGNORE_EXTS,
are not stored properly once the eval is processed.
This causes references to the constant to still have the eval in the
value.
(cherry picked from commit f0aa31b49e)

lib/ansible/constants.py

@@ -108,6 +108,6 @@ for setting in config.data.get_settings():
         except:
             value = setting.value
 
-    set_constant(setting.name, setting.value)
+    set_constant(setting.name, value or setting.value)