Finally, i was able to identify the missing piece. This was setting up the environment identifier for the runner. 

    name: "Deploy bundle"
    runs-on: ubuntu-latest
    environment: ${{github.event.inputs.Environment}}

With this, the action was able to get the secrets from the github environment. 

The host property for DATABRICKS_HOST is provided via the bundles configurations, it doesnt need to be provided again on the Github action.