[charts/portal] add cache env for test config

Description of the change adds cache env for test configs

Benefits for testing purpose

Drawbacks none

Applicable issues none

Additional information

Checklist

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

CAAPIM / apim-charts