fix(is_manager_agent_up): ipv6 support
fix(is_manager_agent_up): ipv6 support

was failing with the following exception:
```
requests.exceptions.InvalidURL: Failed to parse: 2a05:d018:eb8:3100:b8c9:4e23:966c:c8c1:10001
```

since we didn't escape the address correctly

scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-longevity-tests,scylladb/scylla-cluster-tests,scylladb/scylla-longevity-tests,scylladb/scylla-cluster-tests,scylladb/scylla-longevity-tests