conformance: specify consul-k8s-control-plane:latest

[mikemorris]

Changes proposed in this PR:

Specify consul-k8s-control-plane:latest image to support installing from Consul Helm chart main branch.

How I've tested this PR:

Running conformance tests, which have been failing in the setup steps (consul-controller and conect-inject-controller pods never become healthy) with Parsing flagset: flag provided but not defined: -consul-api-timeout due to changes in the main branch of the Consul Helm chart but imageK8s defaulting to 0.43.0 still.

How I expect reviewers to test this PR:

Confirm that conformance tests are able to deploy Consul from the Helm chart successfully, and reach expected failures in ReferencePolicy conformance test suite.

Checklist:

• Tests added
• CHANGELOG entry added

  Run make changelog-entry for guidance in authoring a changelog entry, and
  commit the resulting file, which should have a name matching your PR number.
  Entries should use imperative present tense (e.g. Add support for...)

[nathancoleman]

Noting that conformance tests make it through the consul install now and fail in the expected manner. Those failing tests will be addressed by a different PR in the future.