[bitnami/mongodb] Update dns-check init container condition

[migruiz4]

Description of the change

Updates the dns-check init container conditional to not include .Values.externalAccess.service.domain.

The value externalAccess.service.domain didn't interfere in any way with the dns-check init container, which led us to two possible scenarios:

• When externalAccess.service.publicNames is set, the dns-check will ensure that indeed the pod is able to resolve the DNS.
• When externalAccess.service.publicNames is NOT set, but externalAccess.service.domain is, the dns-check will perform a check on the pod's FQDN, e.g. mongodb-0.svc.mongodb-hl.my-ns.cluster.local.

This second scenario doesn't really make sense, because the headless service is configured with publishNotReadyAddresses=true, and performing a DNS check on a headless service is unnecessary.

Benefits

Simplifies the logic and fixes an existing issue with the dns-check init container, where check would never pass because variable MY_POD_NAMESPACE was never defined.

Possible drawbacks

None known.

Applicable issues

• fixes [bitnami/mongodb] dnsCheck needs $MY_POD_NAMESPACE to be set #30798

Checklist

• Chart version bumped in Chart.yaml according to semver. This is not necessary when the changes only affect README.md files.
• Variables are documented in the values.yaml and added to the README.md using readme-generator-for-helm
• 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)

[jotamartos]

The PR LGTM but if we remove usage from .Values.externalAccess.service.domain here, it's almost unused in the chart. I think we can change the logic to use .Values.externalAccess.service.publicNames and remove the other parameter.