[BUG][opensearch-dashboards] selectorLabels generated but not used.

[rcomanne]

Describe the bug opensearch-dashboards.selectorLabels is defined, but never used. Instead the labels for app and chart are used. This makes the selector labels an outlier with the rest of the repository

To Reproduce

1. Check the _helpers.tpl for generation of the selectors
2. Check the selector labels present in the templates themselves
   • deployment.yaml
   • service.yaml

Expected behavior I'd expect the selector labels to be properly used.

Chart Name opensearch-dashboards

Host/Environment (please complete the following information): Not relevant.

[peterzhuamazon]

Hi @rcomanne can you raise another PR with DCO signed (just use -s when you run git commit).

Thanks.