Potential fix for code scanning alert no. 62: Unused variable, import, function or class

[MSNev]

Potential fix for https://github.com/microsoft/DynamicProto-JS/security/code-scanning/62

To fix the problem, we need to remove the unused variable UNDEFINED from the code. This involves deleting the line where UNDEFINED is declared. This change will not affect the existing functionality of the code since UNDEFINED is not used anywhere.

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