Backport of peering: peering partition failover fixes into release/1.14.x

[hc-github-team-consul-core]

Backport

This PR is auto-generated from #16673 to be assessed for backporting due to the inclusion of the label backport/1.14.

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The person who merged in the original PR is:
@ndhanushkodi
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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The discovery chain clears out the partition field, but when an upstream is imported into a non-default partition, we need to use that source partition when looking up that upstream. This fixes a couple of cases where that was excluded.

PR Checklist

• updated test coverage
• external facing docs updated
• not a security concern

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Overview of commits

• b3bc168

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2 out of 3 committers have signed the CLA.

• ndhanushkodi
• nathancoleman
• temp

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

Auto approved Consul Bot automated PR

[nathancoleman]

Closing since change was manually backported in #16693