Backport of fix: NET-1521 show latest config in /v1/agent/self into release/1.14.x

[hc-github-team-consul-core]

Backport

This PR is auto-generated from #18681 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:
@nvanthao
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 is to fix issue NET-1521 where /v1/agent/self currently not reflecting latest reloadable config

Before the PR, updating reloadable config and run consul reload, the API still show old original config

Original config

bootstrap   = true
server      = true
data_dir    = "/tmp/server"
log_level   = "WARN"
bind_addr   = "127.0.0.1"
client_addr = "127.0.0.1"
raft_snapshot_threshold = 500

Updated config

bootstrap   = true
server      = true
data_dir    = "/tmp/server"
log_level   = "DEBUG"
bind_addr   = "127.0.0.1"
client_addr = "127.0.0.1"
raft_snapshot_threshold = 1000

$ consul reload
Configuration reload triggered

Before the PR

$ curl -s 0:8500/v1/agent/self\?pretty | grep LogLevel
            "LogLevel": "WARN",

$ curl -s 0:8500/v1/agent/self\?pretty | grep RaftSnapshotThreshold
        "RaftSnapshotThreshold": 500,

After the PR

$ curl -s 0:8500/v1/agent/self\?pretty | grep LogLevel
            "LogLevel": "DEBUG",
$ curl -s 0:8500/v1/agent/self\?pretty | grep RaftSnapshotThreshold
        "RaftSnapshotThreshold": 1000,

Testing & Reproduction steps

I have tested the changes manually with above config. However, my unit test is not passing. It will be great if someone could help me with guidance on improving the unit test.

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

• ae2ed84 - b2a9b7a

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

Auto approved Consul Bot automated PR

[nvanthao]

Closing issue as backport is manually created