Add extraObjects and kubecost PR testing workflow

[jessegoodier]

This PR mainly adds the workflow for Kubecost tests.

TODO: add cloudability test

Also add extraObjects, which is consistent with Kubecost helm chart to facilitate testing and other use cases like externalSecrets, etc

Fixed some formatting to pass the tests

currently passing the test:

[gitguardian]

⚠️ GitGuardian has uncovered 1 secret following the scan of your pull request.

Please consider investigating the findings and remediating the incidents. Failure to do so may lead to compromising the associated services or software components.

🔎 Detected hardcoded secret in your pull request

GitGuardian id	GitGuardian status	Secret	Commit	Filename
7414	Triggered	Google API Key	1ecf376	charts/finops-agent/templates/csp-api-key-secret.yaml	View secret

🛠 Guidelines to remediate hardcoded secrets

1. Understand the implications of revoking this secret by investigating where it is used in your code.
2. Replace and store your secret safely. Learn here the best practices.
3. Revoke and rotate this secret.
4. If possible, rewrite git history. Rewriting git history is not a trivial act. You might completely break other contributing developers' workflow and you risk accidentally deleting legitimate data.

To avoid such incidents in the future consider

• following these best practices for managing and storing secrets including API keys and other credentials
• install secret detection on pre-commit to catch secret before it leaves your machine and ease remediation.

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^{🦉 GitGuardian detects secrets in your source code to help developers and security teams secure the modern development process. You are seeing this because you or someone else with access to this repository has authorized GitGuardian to scan your pull request.}

[jessegoodier]

working again: https://github.com/kubecost/finops-agent-chart/actions/workflows/helm-validation.yaml