fix: Add extraEnv option to Helm chart

[gnadaban]

Description

This is a small fix to account for the lack of ability to add extra env vars to the trivy-operator deployment.
This allows specifying eg. AWS IAM session names and other options for eg. secret injection.

Related issues

• Close Support for extra env vars in Helm chart #2287

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• I've added tests that prove my fix is effective or that my feature works.
• I've updated the documentation with the relevant information (if needed).
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