Backport of CI Split integration tests to run nightly and every PR into release/1.15.x

[hc-github-team-consul-core]

Backport

This PR is auto-generated from #18518 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
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the merge conflict occurred.

The person who merged in the original PR is:
@huikang
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

This PR splits our integration test into 2 sets: one keeps being triggered on every PR and the other to run nightly.

Tests to run on every PR

• Vault, nomad test
• compatibility test
• Peering test
• Envoy version 1.27

Tests to run nightly

• Upgrade test
• Envoy versions ["1.24.10", "1.25.9", "1.26.4"]

The reason we split envoy versions is because the dozens of envoy tests run on xlarge runner and each takes 5mintes to complete (link to a recent run).

Backport PR will be made manually due to the version conflict.

Testing & Reproduction steps

Links

PR Checklist

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

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Overview of commits

• 65afa62 - 9984bfd

[hashicorp-cla]

All committers have signed the CLA.

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

Auto approved Consul Bot automated PR