Fix K8S_CLUSTER_URL discovery when running as a K8s job

[PatAKnight]

Summary

Fixes a bug where the K8S_CLUSTER_URL isn't discovered when running as a job. This fix resolves that problem by checking if the scripts are running inside the cluster and then querying for the api endpoint of the cluster.

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• New plugin support (adds integration for a new RHDH plugin)
• Documentation update
• Refactoring (no functional changes)
• CI/CD changes

Related Issues

Closes #(issue number)

Changes Made

• Change 1
• Change 2
• Change 3

Checklist

General

• I have read the CONTRIBUTING guide
• My code follows the project's code conventions
• I have tested my changes against a real cluster
• If upgrading RHDH version, verified values.yaml is compatible with new chart

Security

• No secrets, tokens, or credentials are included in this PR
• Secret templates contain only placeholders (empty strings or <PLACEHOLDER>)
• No hardcoded cluster URLs or API endpoints

For Plugin Contributions

• Documentation added in docs/<plugin-name>.md
• Configuration script added in scripts/config-<plugin-name>-plugin.sh
• config-plugins.sh updated with new mappings
• Secret templates updated with new placeholders
• Resource manifests added (if required)
• All new scripts are executable (chmod +x)

Testing Notes

Describe how you tested these changes:

Screenshots (if applicable)

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