feat: Helm test workflow

[Goku2099]

Following the recent review feedback, this PR moves Helm unit tests into a dedicated workflow (test-helm.yaml).

The goal is to keep the Code Quality workflow focused strictly on linting, while Helm-related tests run separately. This keeps responsibilities clear and makes it easier to extend Helm testing in the future (for example, adding Helm E2E tests).

This change follows the discussion in #3224

This PR supersedes #3166.

[google-oss-prow]

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[Copilot]

Pull request overview

This PR introduces a dedicated Helm test workflow to run Helm unit tests separately from code quality checks. It creates test-helm.yaml that executes make helm-unittest, which runs the helm-unittest plugin against test files in the charts directory. This follows the separation of concerns discussed in #3224, keeping test workflows focused and extensible.

Changes:

• Added .github/workflows/test-helm.yaml to run Helm unit tests on pull requests and pushes

[andreyvelich]

Let's keep it consistent with Go/Python

Suggested change

	helm-tests:
	test:

[andreyvelich]

Can we name it as:

Suggested change

	name: Helm Tests
	name: Unit and Integration Test - Helm

[andreyvelich]

Please can you open an issue to add E2E tests with Helm to this workflow?

We can do that in the next PRs.

[andreyvelich]

Why do we need go?