Stop producing continuous log messages about failed connection to offline daemons and skipping their logs fetch

The issue was reported on our mailing list.

Stork agent produces a log message about a problem with connecting to offline daemons and skipping fetching their logs every 10 seconds.

agent-kea-ha1-1  | time="2024-06-13 15:30:39" level="warning" msg="Problem connecting to dhcp daemon" file="  promkeaexporter.go:147  " error="non-success response result from Kea: 1, text: unable to forward command to the dhcp6 service: No such file or directory. The server is likely to be offline"
agent-kea-ha1-1  | time="2024-06-13 15:30:39" level="warning" msg="Skipped refreshing viewable log files because config-get returned unsuccessful result" file="              kea.go:68   " error="non-success response result from Kea: 1, text: unable to forward command to the d2 service: No such file or directory. The server is likely to be offline"
agent-kea-ha1-1  | time="2024-06-13 15:30:39" level="warning" msg="Skipped refreshing viewable log files because config-get returned unsuccessful result" file="              kea.go:68   " error="non-success response result from Kea: 1, text: unable to forward command to the dhcp6 service: No such file or directory. The server is likely to be offline"

Steps to reproduce:

1. Run Kea CA instance with some control sockets of offline/not running daemons.
2. Run Stork agent.
3. Register and authorize the agent in the Stork server.
4. Observe the problem in Stork agent logs.