[charts/portal] Release 5.1.2.1

Description of the change

Image upgrade for 5.1.2.1 release

Benefits

Latest Portal release

Drawbacks

n/a

Applicable issues

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

CAAPIM / apim-charts