meraki_config_template - Enable check mode (#54502)

* Add support for check mode

* Check mode returns proper changed status
- Added is_template_valid()
- Restructured check_mode so it will always return data
- Check mode should show proper changed status
- Code is untested and integration tests need to be expanded

* Fix deleting networks
- Add integration tests for deleting networks
- Refine tests based on changed/unchanged

* Remove one task from integration test

lib/ansible/module_utils/network/meraki/meraki.py

@@ -61,6 +61,7 @@ class MerakiModule(object):
         self.nets = None
         self.org_id = None
         self.net_id = None
+        self.check_mode = module.check_mode
 
         # normal output
         self.existing = None