Backport of Allow client template config block to be parsed when using json config into release/1.8.x

[hc-github-team-nomad-core]

Backport

This PR is auto-generated from #24007 to be assessed for backporting due to the inclusion of the label backport/1.8.x.

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

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cat ./debug/config.json
{
  "bind_addr": "0.0.0.0",
  "client": {
    "cni_config_dir": "/etc/nomad/cni.d",
    "cni_path": "/usr/libexec/cni",
    "enabled": true,
    "max_dynamic_port": 20010,
    "min_dynamic_port": 20000,
    "servers": [
      "nomad-server-001.internal"
    ],
    "template": {
      "wait": {
        "max": "15s",
        "min": "5s"
      },
      "wait_bounds": {
        "max": "15s",
        "min": "5s"
      }
    }
  },
  "consul": {
    "address": "consul.internal:8500"
  },
  "data_dir": "/opt/nomad/data",
  "datacenter": "dc1",
  "name": "nomad-client-001",
  "telemetry": {
    "collection_interval": "1s",
    "disable_hostname": true,
    "prometheus_metrics": true,
    "publish_allocation_metrics": true,
    "publish_node_metrics": true
  },
  "vault": {
    "address": "https://vault.services.internal",
    "enabled": true
  }
}

Btw I think the artifacts block will have the same problem

Fixes #24001

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Overview of commits

• 4a74fda

[tgross]

Not sure why copywrite is picking up the generated files, but not a blocker.