[charts/portal] Disable 5.1.1 release and introduce only the bitnami chart fixes

[ksaladi]

Description of the change

Fixing the stable branch to disable the Portal 5.1.1 SaaS release

Benefits

Enable customers to still have the 5.1 public release and have the bitnami repo URL fix

Drawbacks

NA

Applicable issues

Bitnami URL fix during "helm dependency" commands

Additional information

Checklist

• [x] Chart version bumped in Chart.yaml according to semver.
• [x] Variables are documented in the README.md
• [x] Title of the PR starts with chart name (e.g. [charts/gateway])
• [x] If the chart contains a values-production.yaml apart from values.yaml, ensure that you implement the changes in both files