Fix: combine image and version field for initHelper of chart in opensearch-cluster (>=3.0.0)

[YeonghyeonKO]

Description

• For a quick fix to this issue (without any change in templates), I used an image field in the opensearch-cluster chart and deployed it. I would recommend this stopgap for the current release version.

# initHelper configuration
initHelper:
  image: "harbor.abc.com/nexus/docker-mig/library/busybox:1.31.1"
  imagePullPolicy: IfNotPresent

• However, if opensearch-k8s-operator follows the principle of specifying the version of image separately like spec.dashboards or spec.general, I suggest to fix it by:

  {{- with .Values.cluster.dashboards }}
  dashboards:
    {{- omit . "image" | toYaml | nindent 4 }}
    image: {{ .image }}:{{ .version }}
  {{- end }}
  {{- with .Values.cluster.general }}
  general:
    {{- omit . "image" "serviceName" | toYaml | nindent 4 }}
    image: {{ .image }}:{{ .version }}
    serviceName: {{ .serviceName | default $clusterName }}
  {{- end }}
  {{- with .Values.cluster.initHelper }}
    {{- omit . "image" | toYaml | nindent 4 }}
    image: {{ .image }}:{{ .version }}
  {{- end }}

Issues Resolved

• [BUG] initHelper setting of values.yaml in opensearch-cluster-3.1.0 #1039

Check List

• Commits are signed per the DCO using --signoff
• Unittest added for the new/changed functionality and all unit tests are successful
• Customer-visible features documented
• No linter warnings (make lint)

If CRDs are changed:

• CRD YAMLs updated (make manifests) and also copied into the helm chart
• Changes to CRDs documented

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[YeonghyeonKO]

It seems enough to add image field like spec.dashboards for now, but it anyone has a better idea, feel free to share your suggestion.

[rootxrishabh]

@YeonghyeonKO thanks for the PR!
I feel this should be sufficient.

[YeonghyeonKO]

in sync with the design of CRD version 2.8.0

• https://github.com/opensearch-project/opensearch-k8s-operator/blob/v2.8.0/docs/designs/crd.md?plain=1#L577

[YeonghyeonKO]

Thanks for reviewing the PR, @rootxrishabh !
If there's any remaining issues, feel free to ping me.
cc: @prudhvigodithi