bitnami/logstash fix: support NodePorts in bitnami logstash chart

[cbrwflo]

Description of the change

Omits the nodePort field on the logstash headless service.

This fixes the error spec.ports[1].nodePort: Forbidden: may not be used when type is 'ClusterIP'

Applicable issues

Fixes:

• [bitnami/logstash] Can't create NodePort through logstash helm chart  #17482
• [bitnami/logstash] Can't create NodePort through logstash helm chart #15393
• [bitnami/logstash] Can't manually attribute port number for NodePort #6278

Additional information

I didn't see a consistent way of expanding the service.spec.ports for headless services across bitnami charts, so I modelled this after the fluentd headless service.

The field service.spec.ports.name is an optional field (when only 1 port is used), so I opted to use service.spec.port.port instead (a required field). I don't love the nested omit, and happy to change the PR to "expand" the fields instead if you prefer.

Checklist

• Chart version bumped in Chart.yaml according to semver. This is not necessary when the changes only affect README.md files.
• Title of the pull request follows this pattern [bitnami/<name_of_the_chart>] Descriptive title
• All commits signed off and in agreement of Developer Certificate of Origin (DCO)