False positive: Env var is from config, not vault, and contains the name of another env var

**Description of the false positive**

This flagged for outputting the value of an environment variable to logs. Generally, that could be a problem. In this case, the env var clearly contained the name of another env var to look in for the secret. Is there a way to not flag in this situation? For example, could we determine that this environment variable came from a k8s env var (where secrets are not allowed) as opposed to from vault?

**Code samples or links to source code**

https://github.com/github/blackbird/blob/d5fc30382331e6f5cd03c7f8695afadeeb631075/crates/config/src/embeddings.rs#L76-L79

**URL to the alert on GitHub code scanning (optional)**

https://github.com/github/blackbird/security/code-scanning/5068

Start with the linked code in crates/config/src/embeddings.rs at lines 76-79 and inspect code-scanning alert 5068 to identify the CodeQL query and data-flow path producing the finding. Done means this configuration value is no longer reported as secret output while genuine environment-variable secret exposure remains detected.

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