fix panic when the runtime config is null

[SungJin1212]

This PR fixes a panic that occurs when clearing all runtime configurations via a Helm chart. The panic was caused by the runtime config being null. This PR adds a check to handle the null case and prevent the crash.

How to reproduce

Clear all runtime_config in the helm chart like:

runtimeconfigmap:
  create: true
  annotations: {}
  runtime_config:

Which issue(s) this PR fixes:
Fixes #

Checklist

• Tests updated
• Documentation added
• CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX]