Backport of [Feature] Invalidate session check if associated session is deleted into release/1.20.x

[srahul3]

Backport

This PR is auto-generated from #22227 to be assessed for backporting due to the inclusion of the label backport/1.20.

The person who merged in the original PR is:
@srahul3
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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Background

The ESM is also requested to go agentless, being agentless it becomes challenging to keep track of the health of the artificial node.

Proposal

This pull request introduces a new feature to support Consul Session to update the state of the health-checks. The constraint is, the health-check needs to be of type session and both session and the health-check shall belong to common parent node.

The idea is to use the sessions to keep track of health status. During partition of ESM crash, the session is deleted and hence, the changes in this PR enables to make the associated session checks to be critical. On thus event, the other ESM instance picks up the leadership and re-distribute the responsibility among remaining health ESM instances.

There is need for a regular session to be created with name <session-name>
There is new check which is proposed of type Type="session" and Definition.SessionName=<session-name>.

** Code sequence **

1. Session invalidates / ttl timer to no reset
2. Session is destroyed
3. The destruction process also checks if the session node has as special check of type session. This session health-check also has a field which suggest the session name. If this check's session name matches with this session name, the check's name is marked critical.

Testing

Unit test added

PR Checklist

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

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Overview of commits

• 29ea0e5 - 8566684 - d753c06

[nitin-sachdev-29]

LGTM

[srahul3]

Backport of the original PR