Backport

This PR is auto-generated from #1804 to be assessed for backporting due to the inclusion of the label backport/1.0.x.

The below text is copied from the body of the original PR.

This PR updates the logic in MatchesConsul for intentions to add partition/namespace to the list of ignored fields for the SourceIntention list to match the ignored fields on the top-level config entry struct. This is to fix an issue where upgrading from Consul pre-1.12 to 1.12+ can trigger an update of all config entries due to the partition/namespace fields in the SourceIntentions from Consul being filled in as "default" instead of "".

Here's what the entry coming from consul 1.12+ looks like:

{
  "Kind": "service-intentions",
  "Name": "*",
  "Partition": "default",
  "Namespace": "default",
  "Sources": [
    {
      "Name": "foo",
      "Partition": "default",
      "Namespace": "default",
      "Action": "allow",
      ...
    }
  ],
  ...
}

And this is what consul-k8s generates via the ToConsul function:

{
  "Kind": "service-intentions",
  "Name": "*",
  "Sources": [
    {
      "Name": "foo",
      "Action": "allow",
      ...
    }
  ],
  ...
}

How I've tested this PR:
Created a consul 1.11.1+ent cluster alongside consul-k8s with a couple basic service intention config entries, then upgraded to 1.12.3+ent. Without this change there's an update to each intention because of the diff/MatchesConsul returns false.

How I expect reviewers to test this PR:

Checklist:

• Tests added
• CHANGELOG entry added