[4.21/main] CloudStack agent does not reconnect to management server

### problem

this issue is found after the testing
https://github.com/apache/cloudstack/blob/main/test/integration/smoke/test_ms_maintenance_and_safe_shutdown.py

The test itself is successful. However, sometimes KVM host (cloudstack-agent) is disconnected. It does not reconnect to the management server. The management server tells the agent that itself is in avoid list when user prepares for management server shutdown or maintenance.

https://github.com/apache/cloudstack/blob/99863c2fa5a57d8ddf1b4b40c647b159d96dc74c/agent/src/main/java/com/cloud/agent/Agent.java#L642

if the `host` setting has only 1 management server IP, the kvm host will not reconnect, even when the management server is back to normal.

### versions

4.21/main

### The steps to reproduce the bug

1. run smoke test `test_ms_maintenance_and_safe_shutdown.py`
2. check the agent state of hosts or system vms
3. if they are Up, run the smoke test again
...

### What to do about it?

_No response_