[FLINK-29086] Fix the Helm chart's pod env params reference

[haoxins]

Contribution Checklist

What is the purpose of the change

Fix the Helm chart's env vars params

Brief change log

Verifying this change

Helm chart small fix

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): (no)
• The public API, i.e., is any changes to the CustomResourceDescriptors: (no)
• Core observer or reconciler logic that is regularly executed: (no)

Documentation

• Does this pull request introduce a new feature? (no)
• If yes, how is the feature documented? (not applicable / docs / JavaDocs / not documented)