[bitnami/redis] fix: update JSON schema to allow string values for values passed to tpl

[piccit]

Description of the change

Updates all properties in values.schema.json that are directly passed to tpl to also allow for string fields.

Benefits

Fixes schema to allow passing strings to tpl for all values that are template-able

Possible drawbacks

None

Applicable issues

• fixes #29451

Additional information

None

Checklist

• [x] Chart version bumped in Chart.yaml according to semver. This is not necessary when the changes only affect README.md files.
• [x] Variables are documented in the values.yaml and added to the README.md using readme-generator-for-helm
• [x] Title of the pull request follows this pattern [bitnami/] Descriptive title
• [x] All commits signed off and in agreement of Developer Certificate of Origin (DCO)