Add enable toggle to test-connection pod

[nickozilla]

What this PR does / why we need it :

Add testConnection.enabled flag to conditionally deploy test connection pod

The test-connection pod is a Helm test hook intended for validating connectivity during chart development and testing. It should not run in production environments.

This change adds a testConnection.enabled value (defaults to true for backwards compatibility) that gates whether the pod manifest is rendered at all.

Changes

• charts/openmetadata/templates/tests/test-connection.yaml — wrapped the Pod manifest in {{- if .Values.testConnection.enabled }}
• charts/openmetadata/values.yaml — added testConnection.enabled: true
• charts/openmetadata/README.md — documented the new value

Context: This chart is deployed via helm template + kustomize rather than helm install. In that workflow, Helm hook annotations (helm.sh/hook: test) are not honoured — all rendered resources are applied directly to the cluster.
The test connection pod was therefore being deployed unconditionally on every upgrade. Adding testConnection.enabled (defaulting to true) allows it to be disabled in environments where it should not run.

Type of change :

• Bug fix
• Improvement
• New feature
• Documentation

Checklist:

• I have read the CONTRIBUTING document.
• Chart Version bumped
• Variables are documented in the README.md
• Title of the PR starts with chart name
• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• All new and existing tests passed.

Reviewers