Bug: changing origin endpoint from FQDN to IP puts the httpproxy is pending state

[zachsmith1]

Context/Problem:

• If you change the origin for a proxy to be an IP when it was originally an FQDN (or the inverse) the gateway controller tries to override/update the endpointslice but this field (AddressType) is immutable.

Solution:

• If we are switching between FQDN and IP, we need to delete the endpointslice before creating the new one instead of trying to update an immutable field