Add missing "connection" JSON property

[S-Bryce]

As of the new version of Wazuh (v4.4), the returned JSON by /overview/agents appears to have changed to be the following:

      "agent_status" : {
         "configuration" : {
            "synced" : X,
            "not_synced" : X,
            "total" : X
         },
         "connection" : {
            "disconnected" : X,
            "pending" : X,
            "total" : X,
            "active" : X,
            "never_connected" : X
         }
      }

Which is causing accesses like agents["agent_status"]["active"] to fail and throw a KeyError, e.g.:

Traceback (most recent call last):
  File "./main.py", line 540, in <module>
    REGISTRY.register(WazuhCollector())
  File "/usr/local/lib/python3.8/site-packages/prometheus_client/registry.py", line 40, in register
    names = self._get_names(collector)
  File "/usr/local/lib/python3.8/site-packages/prometheus_client/registry.py", line 80, in _get_names
    for metric in desc_func():
  File "./main.py", line 93, in collect
    "wazuh_active_agents", value=agents["agent_status"]["active"], labels={}
KeyError: 'active'

This PR addresses this by adding the connective JSON property "connection" to such accesses (e.g., agents["agent_status"]["connection"]["active"]).

[pyToshka]

@S-Bryce thank you for your pr, unfortunately if response has been changed for version 4.4, exporter will stop working for old versions

[S-Bryce]

@S-Bryce thank you for your pr, unfortunately if response has been changed for version 4.4, exporter will stop working for old versions

Good point! I think it should be possible to check the version of the server and have a conditional for which method to use based on the server's version, or even more simply check to see if the "connnection" key exists at all and if not use the old method.

Will make some edits and push a backwards-compatible update

[S-Bryce]

Alright @pyToshka , the PR should support versions below 4.4 now

[S-Bryce]

Have you had a chance to look over the backwards compatibility changes @pyToshka? Sorry to be a bother.