Backport of Updates upgrade docs to clarify Nomad bug is fixed into stable-website

[hc-github-team-consul-core]

Backport

This PR is auto-generated from #14093 to be assessed for backporting due to the inclusion of the label type/docs-cherrypick.

WARNING automatic cherry-pick of commits failed. Commits will require human attention.

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

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Original PR: https://github.com/hashicorp/consul/pull/13946

Description

We on the Nomad team have gotten questions about when it is safe to upgrade Consul when using Nomad Enterprise because of this line of docs.

I am updating the docs to clarify that this issue has been fixed in 1.12.1 and later.

[hashicorp-cla]

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[kisunji]

Already merged: https://github.com/hashicorp/consul/pull/14095