Backport of Add HOST_IP environment variable to consul_dataplane_sidecar.go into release/1.1.x

[hc-github-team-consul-core]

Backport

This PR is auto-generated from #4277 to be assessed for backporting due to the inclusion of the label backport/1.1.x.

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

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[!NOTE] This is sourced from https://github.com/hashicorp/consul-k8s/pull/3916. I needed to open here so that CI requiring tokens that are unavailable in forks can run

Changes proposed in this PR

• Add HOST_IP environment variable to consul_dataplane_sidecar.go

This environment variable must be set in order to utilize HOST_IP as part of statsd or dogstatsd sinks. If this variable is unset and the sink is configured to use HOST_IP, the sidecar won't start and pods won't come up healthy.

How I've tested this PR

• Unit tests
• Deployed and tested a local build to our cluster and confirmed that injected pods now come up healthy and have the HOST_IP variable set as expected

How I expect reviewers to test this PR

• The unit tests should do it

  Reference to similar change for mesh-gateway deployments:

  • https://github.com/hashicorp/consul-k8s/blob/8ac97bf0dc70576e01ade4337700c9f78ed54908/CHANGELOG.md?plain=1#L763
  • https://github.com/hashicorp/consul-k8s/pull/1808

Checklist

• [x] Tests added
• [x] CHANGELOG entry added

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Overview of commits

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