Fix ironic interface option for ironic-inspector

The correct option to use is valid_interfaces [1], not os_endpoint_type.
The os_endpoint_type option was removed in Train.

[1] https://docs.openstack.org/ironic-inspector/wallaby/configuration/sample-config.html

Change-Id: I3906d7b9a2bebfe5c323cba5f80add3e932468c8
Closes-Bug: #1995246
Related-Bug: #1990675