[charts/portal] <do-not-merge>Portal 5.1 changes description from 5.0.2

[ksaladi]

Description of the change

Release notes of Portal 5.1

Benefits

NA

Drawbacks

NA

• fixes #

NA

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