Relates to: https://github.com/apache/pulsar-helm-chart/issues/290
### Motivation
We should not use GitHub Actions to release the helm chart. As such, we can remove the relevant workflow code from this repo while we build the relevant process to officially release the helm chart.
The main risk with this kind of change is that we won't have a way to "release" the chart. However, it is relevant to point out that we have not had any official releases of the chart given that the PMC has not been voting on the releases. I think we need to prioritize fixing this process as a community.
### Modifications
* Remove all scripts and configuration files that enabled GitHub Actions to release the helm chart.
### Verifying this change
This is a trivial change.
6a00845670