Backport of CI: do not upload test metrics to datadog on forks into release/1.15.x

[hc-github-team-consul-core]

Backport

This PR is auto-generated from #17448 to be assessed for backporting due to the inclusion of the label backport/1.15.

🚨

Warning automatic cherry-pick of commits failed. If the first commit failed,
you will see a blank no-op commit below. If at least one commit succeeded, you
will see the cherry-picked commits up to, not including, the commit where
the merge conflict occurred.

The person who merged in the original PR is:
@jmurret
This person should manually cherry-pick the original PR into a new backport PR,
and close this one when the manual backport PR is merged in.

merge conflict error: POST https://api.github.com/repos/hashicorp/consul/merges: 409 Merge conflict []

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

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Description

Tested that these changes work on PR from fork: #17445

Testing & Reproduction steps

• create a PR from fork with only docs changes (or anything that does not cause test failures on its own)
• validate checks run successfully

expected results: go-tests and test-integrations pass.

actual results: both workflows fail when trying to upload test coverage data to DataDog because the DD API key is not present (since the fork does not contain it).

PR Checklist

• updated test coverage
• external facing docs updated
• appropriate backport labels added
• not a security concern

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Overview of commits

• ce702d7 - 4f82d46

[github-team-consul-core-pr-approver]

Auto approved Consul Bot automated PR