dnszone: Add support for check_mode.

This patch adds support for check_mode to the dnszone management
module, and provides tests to verify the behavior.

plugins/modules/ipadnszone.py

@@ -570,6 +570,7 @@ def main():
         argument_spec=get_argument_spec(),
         mutually_exclusive=[["name", "name_from_ip"]],
         required_one_of=[["name", "name_from_ip"]],
+        supports_check_mode=True,
     ).ipa_run()