Description of problem:
After pushing the fresh info via rh_cloud plugin, the customer is getting the issue as below when accessing the server information

---
Response body does not conform to specification
'' is not a 'ipv6' Failed validating 'format' in schema['properties']['results']['items']['properties']['system_profile']['properties']['network_interfaces']['items']['properties']['ipv6_addresses']['items']: {'description': 'The ipv6 address of the system', 'example': '0123:4567:89ab:cdef:0123:4567:89ab:cdef', 'format': 'ipv6', 'type': 'string'} On instance['results'][0]['system_profile']['network_interfaces'][0]['ipv6_addresses'][0]: ''
Request Id: e59fb48581ce430b8450a69dea145879
---

Version-Release number of selected component (if applicable):


How reproducible:
100% with the customer data

Steps to Reproduce:
1. Steps below
- Unregistering the content host via Satellite Inventory page
- Remove also from cloud.redhat.com - Red Hat Insights - Inventory page
- Execute the command below on the Content Host
---
# insights-client --unregister && rm -f /etc/insights-client/machine-id && insights-client --register
---

- Push the info via Satellite/rh_cloud plugin

2.
3.

Actual results:

When accessing the server page, we got the info below


---
Response body does not conform to specification
'' is not a 'ipv6' Failed validating 'format' in schema['properties']['results']['items']['properties']['system_profile']['properties']['network_interfaces']['items']['properties']['ipv6_addresses']['items']: {'description': 'The ipv6 address of the system', 'example': '0123:4567:89ab:cdef:0123:4567:89ab:cdef', 'format': 'ipv6', 'type': 'string'} On instance['results'][0]['system_profile']['network_interfaces'][0]['ipv6_addresses'][0]: ''
Request Id: e59fb48581ce430b8450a69dea145879
---

Expected results:

See the correct information with no issues

Additional info: