Fix Mass Assignment in Variables Endpoints (#5955)

* Fix Mass Assignment in Variables Endpoints

* Update packages/server/src/services/variables/index.ts

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

* Fix Mass Assignment in Variables Endpoints

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Co-authored-by: christopherholland-workday <christopher.holland+evisort@workday.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
Co-authored-by: yau-wd <yau.ong@workday.com>