update cfg mgr exit method

[rekup]

When we use module.fail_json in our modules, this will cause our config managers __exit__ function to raise an exception. This will cause Ansible to display a warning (Module invocation had junk after the JSON data):

TASK [Converge - Set preserve logs] **************************************************************************************************************************
[WARNING]: Module invocation had junk after the JSON data: Exception occurred: 1
fatal: [opnsense]: FAILED! => {"changed": false, "msg": "Parameter max_log_file_size_mb is not supported in OPNsense 23.1"}

This is probably ok if the error was caused by an unhandled exception, but it's not what we expect if we handle an error in our module and deliberately call module.fail_json. This PR fixes the by raising any SystemExit exceptions "as is" which enables Ansible to correctly recognize the call to module.fail_json without displaying the warning.

[KiLLuuuhh]

looks good to me 👍