ci: adding workflow dispatch to helm-chart workflow

[pauldotyu]

Reason for Change:
To be able to run helm chart publish workflows on demand. I noticed the latest version (0.3.0) of the helm chart is not published to https://azure.github.io/kaito/charts/kaito and looks like this can be resolved by simply re-running the publish workflow (without creating a new release).

Confirmed this works in my fork of the kaito repo. Re-running the workflow published new chart version 0.3.0 (with app version 0.3.0)

Requirements

• added unit tests and e2e tests (if applicable).

Issue Fixed:

Notes for Reviewers:

Verify helm chart and app versions

helm repo add kaito https://azure.github.io/kaito/charts/kaito
helm search repo --versions kaito/workspace
helm search repo --versions kaito/gpu-provisioner

[helayoty]

Thank you for contribution. LGTM